From 5e9b6bae9e183a0682cb3021e16a490c44f74708 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Tue, 20 May 2025 15:28:18 -0400
Subject: [PATCH 01/14] Added special lightweight pre-main class to enable SSI
 inject for Java 6.

---
 dd-java-agent/build.gradle                    |  28 +++-
 .../trace/bootstrap/AgentBootstrapJava6.java  | 153 ++++++++++++++++++
 2 files changed, 178 insertions(+), 3 deletions(-)
 create mode 100644 dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java

diff --git a/dd-java-agent/build.gradle b/dd-java-agent/build.gradle
index 1b2c3804acb..9b6f192a218 100644
--- a/dd-java-agent/build.gradle
+++ b/dd-java-agent/build.gradle
@@ -17,8 +17,30 @@ configurations {
   traceShadowInclude
 }
 
-sourceCompatibility = JavaVersion.VERSION_1_7
-targetCompatibility = JavaVersion.VERSION_1_7
+// Support SSI inject for Java 7.
+tasks.named("compileJava", JavaCompile).configure {
+  sourceCompatibility = JavaVersion.VERSION_1_7
+  targetCompatibility = JavaVersion.VERSION_1_7
+}
+
+// Support SSI inject for Java 6.
+sourceSets {
+  java6 {
+    java {
+      srcDirs = ['src/main/java6']
+    }
+  }
+}
+
+tasks.register('compileJava6', JavaCompile) {
+  classpath = sourceSets.main.compileClasspath
+  source = sourceSets.java6.java
+  destinationDirectory = layout.buildDirectory.dir("classes/java/main")
+  sourceCompatibility = JavaVersion.VERSION_1_6
+  targetCompatibility = JavaVersion.VERSION_1_6
+}
+
+tasks.compileJava.dependsOn compileJava6
 
 /*
  * Several shadow jars are created
@@ -176,7 +198,7 @@ shadowJar generalShadowJarConfig >> {
     attributes(
       "Main-Class": "datadog.trace.bootstrap.AgentBootstrap",
       "Agent-Class": "datadog.trace.bootstrap.AgentBootstrap",
-      "Premain-Class": "datadog.trace.bootstrap.AgentBootstrap",
+      "Premain-Class": "datadog.trace.bootstrap.AgentBootstrapJava6",
       "Can-Redefine-Classes": true,
       "Can-Retransform-Classes": true,
       )
diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
new file mode 100644
index 00000000000..ef143cd118f
--- /dev/null
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
@@ -0,0 +1,153 @@
+package datadog.trace.bootstrap;
+
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.lang.instrument.Instrumentation;
+import java.lang.reflect.Method;
+
+/** Special lightweight pre-main class to enable SSI inject for Java 6. */
+public class AgentBootstrapJava6 {
+  public static void premain(final String agentArgs, final Instrumentation inst) {
+    agentmain(agentArgs, inst);
+  }
+
+  public static void agentmain(final String agentArgs, final Instrumentation inst) {
+    try {
+      String version = System.getProperty("java.version");
+      // Found Java 6
+      if (version.startsWith("1.6")) {
+        reportUnsupportedJava6(version);
+      } else {
+        continueBootstrap(agentArgs, inst);
+      }
+    } catch (Throwable e) {
+      error("Agent pre-main function failed", e);
+    }
+  }
+
+  private static void error(String msg, Throwable e) {
+    log(msg + ": " + e.getMessage());
+  }
+
+  private static void log(String msg) {
+    // We don't have a log manager here, so just print.
+    System.out.println(msg);
+  }
+
+  public static void reportUnsupportedJava6(String javaVersion) {
+    try {
+      String agentVersion = getAgentVersion();
+      log(
+          "Warning: "
+              + agentVersion
+              + " of dd-java-agent is not compatible with Java "
+              + javaVersion
+              + " and will not be installed.");
+      log("Please upgrade your Java version to 8+");
+      String forwarderPath = null;
+      try {
+        forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
+      } catch (SecurityException e) {
+        log("Failed to get DD_TELEMETRY_FORWARDER_PATH: " + e.getMessage());
+      }
+      if (forwarderPath == null) {
+        log("Telemetry forwarder path is null.");
+        return;
+      }
+      String payload =
+          "{\"metadata\":{"
+              + "\"runtime_name\":\"jvm\","
+              + "\"language_name\":\"jvm\","
+              + "\"runtime_version\":\""
+              + javaVersion
+              + "\","
+              + "\"language_version\":\""
+              + javaVersion
+              + "\","
+              + "\"tracer_version\":\""
+              + agentVersion
+              + "\"},"
+              + "\"points\":\"[{"
+              + "\"name\":\"library_entrypoint.abort\","
+              + "\"tags\":[\"reason:incompatible_runtime\"]"
+              + "}]"
+              + "}";
+
+      ForwarderJsonSenderThread t = new ForwarderJsonSenderThread(forwarderPath, payload);
+      t.start();
+
+      try {
+        t.join(1000);
+      } catch (InterruptedException e) {
+        // just for hygiene, reset the interrupt status
+        Thread.currentThread().interrupt();
+      }
+    } catch (Throwable e) {
+      error("Failed to report telemetry", e);
+    }
+  }
+
+  public static String getAgentVersion() {
+    try {
+      // Get the resource as an InputStream
+      InputStream is = AgentBootstrapJava6.class.getResourceAsStream("/dd-java-agent.version");
+      if (is == null) {
+        return "n/a";
+      }
+
+      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+      final StringBuilder sb = new StringBuilder();
+      for (int c = reader.read(); c != -1; c = reader.read()) {
+        sb.append((char) c);
+      }
+      reader.close();
+
+      return sb.toString().trim();
+    } catch (Throwable e) {
+      return "unknown";
+    }
+  }
+
+  private static void continueBootstrap(final String agentArgs, final Instrumentation inst) {
+    try {
+      Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");
+      Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
+      agentMain.invoke(null, agentArgs, inst);
+    } catch (Throwable e) {
+      System.err.println("Failed to install dd-java-agent: " + e.getMessage());
+    }
+  }
+
+  public static final class ForwarderJsonSenderThread extends Thread {
+    private final String forwarderPath;
+    private final String payload;
+
+    public ForwarderJsonSenderThread(String forwarderPath, String payload) {
+      super("dd-forwarder-json-sender");
+      setDaemon(true);
+      this.forwarderPath = forwarderPath;
+      this.payload = payload;
+    }
+
+    @Override
+    public void run() {
+      ProcessBuilder builder = new ProcessBuilder(forwarderPath, "library_entrypoint");
+      try {
+        Process process = builder.start();
+        OutputStream out = null;
+        try {
+          out = process.getOutputStream();
+          out.write(payload.getBytes());
+        } finally {
+          if (out != null) {
+            out.close();
+          }
+        }
+      } catch (Throwable e) {
+        error("Failed to send telemetry", e);
+      }
+    }
+  }
+}

From c40db792e59c074fb25c3970835daa207d03413c Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Tue, 20 May 2025 16:29:39 -0400
Subject: [PATCH 02/14] Fixed SuppressForbidden test.

---
 dd-java-agent/build.gradle                                  | 6 +++++-
 .../java6/datadog/trace/bootstrap/AgentBootstrapJava6.java  | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/dd-java-agent/build.gradle b/dd-java-agent/build.gradle
index 9b6f192a218..d6dc3f93df9 100644
--- a/dd-java-agent/build.gradle
+++ b/dd-java-agent/build.gradle
@@ -40,6 +40,10 @@ tasks.register('compileJava6', JavaCompile) {
   targetCompatibility = JavaVersion.VERSION_1_6
 }
 
+dependencies {
+  java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
+}
+
 tasks.compileJava.dependsOn compileJava6
 
 /*
@@ -90,7 +94,7 @@ ext.generalShadowJarConfig = {
   if (!projectName.equals('instrumentation')) {
     relocate 'org.yaml.snakeyaml', 'datadog.snakeyaml'
     relocate 'okhttp3', 'datadog.okhttp3'
-    relocate 'okio',  'datadog.okio'
+    relocate 'okio', 'datadog.okio'
   }
 
   if (!project.hasProperty("disableShadowRelocate") || !disableShadowRelocate) {
diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
index ef143cd118f..38c5cd45b83 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
@@ -1,5 +1,6 @@
 package datadog.trace.bootstrap;
 
+import de.thetaphi.forbiddenapis.SuppressForbidden;
 import java.io.BufferedReader;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -31,6 +32,7 @@ private static void error(String msg, Throwable e) {
     log(msg + ": " + e.getMessage());
   }
 
+  @SuppressForbidden
   private static void log(String msg) {
     // We don't have a log manager here, so just print.
     System.out.println(msg);
@@ -110,6 +112,7 @@ public static String getAgentVersion() {
     }
   }
 
+  @SuppressForbidden
   private static void continueBootstrap(final String agentArgs, final Instrumentation inst) {
     try {
       Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");

From 125a148af9611978fa9a410ccb9f153211f7bfc3 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Thu, 22 May 2025 22:47:01 -0400
Subject: [PATCH 03/14] Refactored pre-check logic.

---
 dd-java-agent/build.gradle                    |  12 +-
 .../trace/bootstrap/AgentBootstrap.java       |  66 +-----
 .../trace/bootstrap/AgentBootstrapJava6.java  | 156 --------------
 .../trace/bootstrap/AgentPreCheck.java        | 191 ++++++++++++++++++
 .../trace/bootstrap/AgentBootstrapTest.groovy |  91 ---------
 .../trace/bootstrap/AgentPreCheckTest.groovy  | 140 +++++++++++++
 6 files changed, 336 insertions(+), 320 deletions(-)
 delete mode 100644 dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
 create mode 100644 dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
 create mode 100644 dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy

diff --git a/dd-java-agent/build.gradle b/dd-java-agent/build.gradle
index d6dc3f93df9..f001c02fb5e 100644
--- a/dd-java-agent/build.gradle
+++ b/dd-java-agent/build.gradle
@@ -17,13 +17,8 @@ configurations {
   traceShadowInclude
 }
 
-// Support SSI inject for Java 7.
-tasks.named("compileJava", JavaCompile).configure {
-  sourceCompatibility = JavaVersion.VERSION_1_7
-  targetCompatibility = JavaVersion.VERSION_1_7
-}
-
-// Support SSI inject for Java 6.
+// The special pre-check should be compiled with Java 6 to detect unsupported Java versions and
+// prevent issues for users that still using them.
 sourceSets {
   java6 {
     java {
@@ -42,6 +37,7 @@ tasks.register('compileJava6', JavaCompile) {
 
 dependencies {
   java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
+  testImplementation sourceSets.java6.output
 }
 
 tasks.compileJava.dependsOn compileJava6
@@ -202,7 +198,7 @@ shadowJar generalShadowJarConfig >> {
     attributes(
       "Main-Class": "datadog.trace.bootstrap.AgentBootstrap",
       "Agent-Class": "datadog.trace.bootstrap.AgentBootstrap",
-      "Premain-Class": "datadog.trace.bootstrap.AgentBootstrapJava6",
+      "Premain-Class": "datadog.trace.bootstrap.AgentPreCheck",
       "Can-Redefine-Classes": true,
       "Can-Retransform-Classes": true,
       )
diff --git a/dd-java-agent/src/main/java/datadog/trace/bootstrap/AgentBootstrap.java b/dd-java-agent/src/main/java/datadog/trace/bootstrap/AgentBootstrap.java
index ed0db2fc50a..77bc9f8685e 100644
--- a/dd-java-agent/src/main/java/datadog/trace/bootstrap/AgentBootstrap.java
+++ b/dd-java-agent/src/main/java/datadog/trace/bootstrap/AgentBootstrap.java
@@ -9,7 +9,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
-import java.io.PrintStream;
 import java.lang.instrument.Instrumentation;
 import java.lang.reflect.Method;
 import java.net.URI;
@@ -126,10 +125,6 @@ private static void agentmainImpl(
       // since tracer is presumably initialized elsewhere, still considering this complete
       return;
     }
-    if (lessThanJava8()) {
-      initTelemetry.onAbort("incompatible_runtime");
-      return;
-    }
     if (isJdkTool()) {
       initTelemetry.onAbort("jdk_tool");
       return;
@@ -170,7 +165,7 @@ static boolean getConfig(String configName) {
   }
 
   static boolean exceptionCauseChainContains(Throwable ex, String exClassName) {
-    Set<Throwable> stack = Collections.newSetFromMap(new IdentityHashMap<Throwable, Boolean>());
+    Set<Throwable> stack = Collections.newSetFromMap(new IdentityHashMap<>());
     Throwable t = ex;
     while (t != null && stack.add(t) && stack.size() <= MAX_EXCEPTION_CHAIN_LENGTH) {
       // cannot do an instanceof check since most of the agent's code is loaded by an isolated CL
@@ -193,36 +188,6 @@ private static boolean alreadyInitialized() {
     return false;
   }
 
-  @SuppressForbidden
-  private static boolean lessThanJava8() {
-    try {
-      return lessThanJava8(System.getProperty("java.version"), System.err);
-    } catch (SecurityException e) {
-      // Hypothetically, we could version sniff the supported version level
-      // For now, just skip the check and let the JVM handle things instead
-      return false;
-    }
-  }
-
-  // Reachable for testing
-  static boolean lessThanJava8(String version, PrintStream output) {
-    if (parseJavaMajorVersion(version) < 8) {
-      String agentRawVersion = AgentJar.tryGetAgentVersion();
-      String agentVersion = agentRawVersion == null ? "This version" : "Version " + agentRawVersion;
-
-      output.println(
-          "Warning: "
-              + agentVersion
-              + " of dd-java-agent is not compatible with Java "
-              + version
-              + " and will not be installed.");
-      output.println(
-          "Please upgrade your Java version to 8+ or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0");
-      return true;
-    }
-    return false;
-  }
-
   private static boolean isJdkTool() {
     String moduleMain = SystemUtils.tryGetProperty("jdk.module.main");
     if (null != moduleMain && !moduleMain.isEmpty() && moduleMain.charAt(0) == 'j') {
@@ -263,32 +228,6 @@ private static boolean isJdkTool() {
     return false;
   }
 
-  // Reachable for testing
-  static int parseJavaMajorVersion(String version) {
-    int major = 0;
-    if (null == version || version.isEmpty()) {
-      return major;
-    }
-    int start = 0;
-    if (version.charAt(0) == '1'
-        && version.length() >= 3
-        && version.charAt(1) == '.'
-        && Character.isDigit(version.charAt(2))) {
-      start = 2;
-    }
-    // Parse the major digit and be a bit lenient, allowing digits followed by any non digit
-    for (int i = start; i < version.length(); i++) {
-      char c = version.charAt(i);
-      if (Character.isDigit(c)) {
-        major *= 10;
-        major += Character.digit(c, 10);
-      } else {
-        break;
-      }
-    }
-    return major;
-  }
-
   @SuppressForbidden
   static boolean shouldAbortDueToOtherJavaAgents() {
     // We don't abort if either
@@ -333,9 +272,6 @@ static boolean shouldAbortDueToOtherJavaAgents() {
   }
 
   public static void main(final String[] args) {
-    if (lessThanJava8()) {
-      return;
-    }
     AgentJar.main(args);
   }
 
diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
deleted file mode 100644
index 38c5cd45b83..00000000000
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
+++ /dev/null
@@ -1,156 +0,0 @@
-package datadog.trace.bootstrap;
-
-import de.thetaphi.forbiddenapis.SuppressForbidden;
-import java.io.BufferedReader;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.OutputStream;
-import java.lang.instrument.Instrumentation;
-import java.lang.reflect.Method;
-
-/** Special lightweight pre-main class to enable SSI inject for Java 6. */
-public class AgentBootstrapJava6 {
-  public static void premain(final String agentArgs, final Instrumentation inst) {
-    agentmain(agentArgs, inst);
-  }
-
-  public static void agentmain(final String agentArgs, final Instrumentation inst) {
-    try {
-      String version = System.getProperty("java.version");
-      // Found Java 6
-      if (version.startsWith("1.6")) {
-        reportUnsupportedJava6(version);
-      } else {
-        continueBootstrap(agentArgs, inst);
-      }
-    } catch (Throwable e) {
-      error("Agent pre-main function failed", e);
-    }
-  }
-
-  private static void error(String msg, Throwable e) {
-    log(msg + ": " + e.getMessage());
-  }
-
-  @SuppressForbidden
-  private static void log(String msg) {
-    // We don't have a log manager here, so just print.
-    System.out.println(msg);
-  }
-
-  public static void reportUnsupportedJava6(String javaVersion) {
-    try {
-      String agentVersion = getAgentVersion();
-      log(
-          "Warning: "
-              + agentVersion
-              + " of dd-java-agent is not compatible with Java "
-              + javaVersion
-              + " and will not be installed.");
-      log("Please upgrade your Java version to 8+");
-      String forwarderPath = null;
-      try {
-        forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
-      } catch (SecurityException e) {
-        log("Failed to get DD_TELEMETRY_FORWARDER_PATH: " + e.getMessage());
-      }
-      if (forwarderPath == null) {
-        log("Telemetry forwarder path is null.");
-        return;
-      }
-      String payload =
-          "{\"metadata\":{"
-              + "\"runtime_name\":\"jvm\","
-              + "\"language_name\":\"jvm\","
-              + "\"runtime_version\":\""
-              + javaVersion
-              + "\","
-              + "\"language_version\":\""
-              + javaVersion
-              + "\","
-              + "\"tracer_version\":\""
-              + agentVersion
-              + "\"},"
-              + "\"points\":\"[{"
-              + "\"name\":\"library_entrypoint.abort\","
-              + "\"tags\":[\"reason:incompatible_runtime\"]"
-              + "}]"
-              + "}";
-
-      ForwarderJsonSenderThread t = new ForwarderJsonSenderThread(forwarderPath, payload);
-      t.start();
-
-      try {
-        t.join(1000);
-      } catch (InterruptedException e) {
-        // just for hygiene, reset the interrupt status
-        Thread.currentThread().interrupt();
-      }
-    } catch (Throwable e) {
-      error("Failed to report telemetry", e);
-    }
-  }
-
-  public static String getAgentVersion() {
-    try {
-      // Get the resource as an InputStream
-      InputStream is = AgentBootstrapJava6.class.getResourceAsStream("/dd-java-agent.version");
-      if (is == null) {
-        return "n/a";
-      }
-
-      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
-      final StringBuilder sb = new StringBuilder();
-      for (int c = reader.read(); c != -1; c = reader.read()) {
-        sb.append((char) c);
-      }
-      reader.close();
-
-      return sb.toString().trim();
-    } catch (Throwable e) {
-      return "unknown";
-    }
-  }
-
-  @SuppressForbidden
-  private static void continueBootstrap(final String agentArgs, final Instrumentation inst) {
-    try {
-      Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");
-      Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
-      agentMain.invoke(null, agentArgs, inst);
-    } catch (Throwable e) {
-      System.err.println("Failed to install dd-java-agent: " + e.getMessage());
-    }
-  }
-
-  public static final class ForwarderJsonSenderThread extends Thread {
-    private final String forwarderPath;
-    private final String payload;
-
-    public ForwarderJsonSenderThread(String forwarderPath, String payload) {
-      super("dd-forwarder-json-sender");
-      setDaemon(true);
-      this.forwarderPath = forwarderPath;
-      this.payload = payload;
-    }
-
-    @Override
-    public void run() {
-      ProcessBuilder builder = new ProcessBuilder(forwarderPath, "library_entrypoint");
-      try {
-        Process process = builder.start();
-        OutputStream out = null;
-        try {
-          out = process.getOutputStream();
-          out.write(payload.getBytes());
-        } finally {
-          if (out != null) {
-            out.close();
-          }
-        }
-      } catch (Throwable e) {
-        error("Failed to send telemetry", e);
-      }
-    }
-  }
-}
diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
new file mode 100644
index 00000000000..64fd8644af7
--- /dev/null
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -0,0 +1,191 @@
+package datadog.trace.bootstrap;
+
+import de.thetaphi.forbiddenapis.SuppressForbidden;
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.lang.instrument.Instrumentation;
+import java.lang.reflect.Method;
+
+/** Special lightweight pre-main class that skips installation on incompatible JVMs. */
+public class AgentPreCheck {
+  public static final String AGENT_BOOTSTRAP_CLASS = "datadog.trace.bootstrap.AgentBootstrap";
+
+  public static void premain(final String agentArgs, final Instrumentation inst) {
+    agentmain(agentArgs, inst);
+  }
+
+  public static void agentmain(final String agentArgs, final Instrumentation inst) {
+    try {
+      if (compatible()) {
+        agentBootstrapPreMain(agentArgs, inst);
+      }
+    } catch (Throwable e) {
+      // If agent failed we should not fail the application.
+      // We don't have a log manager here, so just print.
+      System.err.println("ERROR: " + e.getMessage());
+    }
+  }
+
+  private static void reportIncompatibleJava(
+      String javaVersion, int majorJavaVersion, String agentVersion, PrintStream output) {
+    output.println(
+        "Warning: "
+            + (agentVersion == null ? "This version" : "Version " + agentVersion)
+            + " of dd-java-agent is not compatible with Java "
+            + javaVersion
+            + " and will not be installed.");
+
+    String msg = "Please upgrade your Java version to 8+";
+    if (majorJavaVersion == 7) {
+      msg +=
+          " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0";
+    }
+    output.println(msg);
+  }
+
+  static void sendTelemetry(String forwarderPath, String javaVersion, String agentVersion) {
+    // Hardcoded payload for unsupported Java version.
+    String payload =
+        "{\"metadata\":{"
+            + "\"runtime_name\":\"jvm\","
+            + "\"language_name\":\"jvm\","
+            + "\"runtime_version\":\""
+            + javaVersion
+            + "\","
+            + "\"language_version\":\""
+            + javaVersion
+            + "\","
+            + "\"tracer_version\":\""
+            + agentVersion
+            + "\"},"
+            + "\"points\":[{"
+            + "\"name\":\"library_entrypoint.abort\","
+            + "\"tags\":[\"reason:incompatible_runtime\"]"
+            + "}]"
+            + "}";
+
+    ForwarderJsonSenderThread t = new ForwarderJsonSenderThread(forwarderPath, payload);
+    t.setDaemon(true);
+    t.start();
+  }
+
+  @SuppressForbidden
+  private static boolean compatible() {
+    return compatible(System.getProperty("java.version"), System.err);
+  }
+
+  // Reachable for testing
+  static boolean compatible(String javaVersion, PrintStream output) {
+    int majorJavaVersion = parseJavaMajorVersion(javaVersion);
+
+    if (majorJavaVersion >= 8) {
+      return true;
+    }
+
+    String agentVersion = getAgentVersion();
+
+    reportIncompatibleJava(javaVersion, majorJavaVersion, agentVersion, output);
+
+    String forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
+    if (forwarderPath != null) {
+      sendTelemetry(forwarderPath, javaVersion, agentVersion);
+    }
+
+    return false;
+  }
+
+  // Reachable for testing
+  static int parseJavaMajorVersion(String javaVersion) {
+    int major = 0;
+    if (javaVersion == null || javaVersion.isEmpty()) {
+      return major;
+    }
+
+    int start = 0;
+    if (javaVersion.charAt(0) == '1'
+        && javaVersion.length() >= 3
+        && javaVersion.charAt(1) == '.'
+        && Character.isDigit(javaVersion.charAt(2))) {
+      start = 2;
+    }
+
+    // Parse the major digit and be a bit lenient, allowing digits followed by any non digit
+    for (int i = start; i < javaVersion.length(); i++) {
+      char c = javaVersion.charAt(i);
+      if (Character.isDigit(c)) {
+        major *= 10;
+        major += Character.digit(c, 10);
+      } else {
+        break;
+      }
+    }
+    return major;
+  }
+
+  private static String getAgentVersion() {
+    try {
+      // Get the resource as an InputStream
+      InputStream is = AgentPreCheck.class.getResourceAsStream("/dd-java-agent.version");
+      if (is == null) {
+        return null;
+      }
+
+      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+      final StringBuilder sb = new StringBuilder();
+      for (int c = reader.read(); c != -1; c = reader.read()) {
+        sb.append((char) c);
+      }
+      reader.close();
+
+      return sb.toString().trim();
+    } catch (Throwable e) {
+      return null;
+    }
+  }
+
+  @SuppressForbidden
+  private static void agentBootstrapPreMain(final String agentArgs, final Instrumentation inst) {
+    try {
+      Class<?> clazz = Class.forName(AGENT_BOOTSTRAP_CLASS);
+      Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
+      agentMain.invoke(null, agentArgs, inst);
+    } catch (Throwable e) {
+      System.err.printf(
+          "Failed to execute %s.agentmain(): %s%n", AGENT_BOOTSTRAP_CLASS, e.getMessage());
+    }
+  }
+
+  public static final class ForwarderJsonSenderThread extends Thread {
+    private final String forwarderPath;
+    private final String payload;
+
+    public ForwarderJsonSenderThread(String forwarderPath, String payload) {
+      super("dd-forwarder-json-sender");
+      setDaemon(true);
+      this.forwarderPath = forwarderPath;
+      this.payload = payload;
+    }
+
+    @Override
+    public void run() {
+      ProcessBuilder builder = new ProcessBuilder(forwarderPath, "library_entrypoint");
+      try {
+        Process process = builder.start();
+        OutputStream out = null;
+        try {
+          out = process.getOutputStream();
+          out.write(payload.getBytes());
+        } finally {
+          if (out != null) {
+            out.close();
+          }
+        }
+      } catch (Throwable e) {
+        System.err.println("Failed to send telemetry: " + e.getMessage());
+      }
+    }
+  }
+}
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentBootstrapTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentBootstrapTest.groovy
index ddeb330b672..6f2cd97fb77 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentBootstrapTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentBootstrapTest.groovy
@@ -3,97 +3,6 @@ package datadog.trace.bootstrap
 import spock.lang.Specification
 
 class AgentBootstrapTest extends Specification {
-  def 'parse java.version strings'() {
-    when:
-    def major = AgentBootstrap.parseJavaMajorVersion(version)
-
-    then:
-    major == expected
-
-    where:
-    version      | expected
-    null         | 0
-    ''           | 0
-    'a.0.0'      | 0
-    '0.a.0'      | 0
-    '0.0.a'      | 0
-    '1.a.0_0'    | 1
-    '1.8.a_0'    | 8
-    '1.8.0_a'    | 8
-    '1.7'        | 7
-    '1.7.0'      | 7
-    '1.7.0_221'  | 7
-    '1.8'        | 8
-    '1.8.0'      | 8
-    '1.8.0_212'  | 8
-    '1.8.0_292'  | 8
-    '9-ea'       | 9
-    '9.0.4'      | 9
-    '9.1.2'      | 9
-    '10.0.2'     | 10
-    '11'         | 11
-    '11a'        | 11
-    '11.0.6'     | 11
-    '11.0.11'    | 11
-    '12.0.2'     | 12
-    '13.0.2'     | 13
-    '14'         | 14
-    '14.0.2'     | 14
-    '15'         | 15
-    '15.0.2'     | 15
-    '16.0.1'     | 16
-    '11.0.9.1+1' | 11
-    '11.0.6+10'  | 11
-  }
-
-  def 'log warning message when java version is less than 8'() {
-    setup:
-    def baos = new ByteArrayOutputStream()
-    def logStream = new PrintStream(baos)
-
-    when:
-    def isLowerThan8 = AgentBootstrap.lessThanJava8(version, logStream)
-    logStream.flush()
-    def logLines = Arrays.asList(baos.toString().split('\n'))
-    // If the list only contains a single String and that is the empty String, then the set is empty
-    if (logLines.size() == 1 && logLines.contains('')) {
-      logLines = []
-    }
-
-    then:
-    isLowerThan8 == expectedLower
-    if (!expectedLower) {
-      assert logLines.isEmpty()
-    } else {
-      assert logLines.size() == 2
-      assert logLines == [
-        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java ${version} and will not be installed.",
-        'Please upgrade your Java version to 8+ or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0'
-      ]
-    }
-
-    where:
-    version      | expectedLower
-    null         | true
-    ''           | true
-    'a.0.0'      | true
-    '0.a.0'      | true
-    '0.0.a'      | true
-    '1.a.0_0'    | true
-    '1.8.a_0'    | false
-    '1.8.0_a'    | false
-    '1.7'        | true
-    '1.7.0'      | true
-    '1.7.0_221'  | true
-    '1.8'        | false
-    '9.0.4'      | false
-    '10.0.2'     | false
-    '11a'        | false
-    '15'         | false
-    '11.0.9.1+1' | false
-
-  }
-
   def 'return true when first exception in the cause chain is the specified exception'() {
     setup:
     def ex = new IOException()
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
new file mode 100644
index 00000000000..a8b3c2897c2
--- /dev/null
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -0,0 +1,140 @@
+package datadog.trace.bootstrap
+
+import spock.lang.Specification
+import spock.util.concurrent.PollingConditions
+
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.attribute.PosixFilePermissions
+
+class AgentPreCheckTest extends Specification {
+  def 'parse java.version of #versionƒ as #expected'() {
+    when:
+    def major = AgentPreCheck.parseJavaMajorVersion(version)
+
+    then:
+    major == expected
+
+    where:
+    version      | expected
+    null         | 0
+    ''           | 0
+    'a.0.0'      | 0
+    '0.a.0'      | 0
+    '0.0.a'      | 0
+    '1.a.0_0'    | 1
+    '1.6'        | 6
+    '1.6.0_45'   | 6
+    '1.7'        | 7
+    '1.7.0'      | 7
+    '1.7.0_221'  | 7
+    '1.8.a_0'    | 8
+    '1.8.0_a'    | 8
+    '1.8'        | 8
+    '1.8.0'      | 8
+    '1.8.0_212'  | 8
+    '1.8.0_292'  | 8
+    '9-ea'       | 9
+    '9.0.4'      | 9
+    '9.1.2'      | 9
+    '10.0.2'     | 10
+    '11'         | 11
+    '11a'        | 11
+    '11.0.6'     | 11
+    '11.0.11'    | 11
+    '12.0.2'     | 12
+    '13.0.2'     | 13
+    '14'         | 14
+    '14.0.2'     | 14
+    '15'         | 15
+    '15.0.2'     | 15
+    '16.0.1'     | 16
+    '11.0.9.1+1' | 11
+    '11.0.6+10'  | 11
+    '17.0.15'    | 17
+    '21.0.7'     | 21
+  }
+
+  def 'log warning message when java is not compatible'() {
+    setup:
+    def output = new ByteArrayOutputStream()
+    def logStream = new PrintStream(output)
+
+    when:
+    boolean compatible = AgentPreCheck.compatible(javaVersion, logStream)
+    String log = output.toString()
+    def logLines = log.isEmpty() ? [] : Arrays.asList(log.split('\n'))
+
+    then:
+    compatible == expectedCompatible
+
+    if (expectedCompatible) {
+      assert logLines.isEmpty()
+    } else {
+      logLines.size() == 2
+      def expectedLogLines = [
+        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java ${javaVersion} and will not be installed.",
+        "Please upgrade your Java version to 8+" + (AgentPreCheck.parseJavaMajorVersion(javaVersion) == 7 ? " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0" : "")
+      ]
+      assert logLines == expectedLogLines
+    }
+    where:
+    javaVersion | expectedCompatible
+    null        | false
+    ''          | false
+    '1.6.0_45'  | false
+    '1.7.0_221' | false
+    '1.8.0_212' | true
+    '11.0.6'    | true
+    '17.0.15'   | true
+    '21.0.7'    | true
+  }
+
+  def 'send hardcoded bootstrap telemetry for unsupported java'() {
+    setup:
+    Path path = Files.createTempFile('test-forwarder', '.sh', PosixFilePermissions.asFileAttribute(PosixFilePermissions.fromString('rwxr--r--')))
+    File forwarderFile = path.toFile()
+    forwarderFile.deleteOnExit()
+
+    String forwarderPath = forwarderFile.getAbsolutePath()
+
+    File outputFile = new File(forwarderPath + '.out')
+    outputFile.deleteOnExit()
+
+    def script = [
+      '#!/usr/bin/env bash',
+      'echo "$1	$(cat -)" >>' + outputFile.getAbsolutePath(),
+      ''
+    ]
+
+    forwarderFile << script.join('\n')
+
+    when:
+    AgentPreCheck.sendTelemetry(forwarderPath, '1.6.0_45', '1.50')
+
+    then:
+    new PollingConditions().within(5) {
+      assert outputFile.exists()
+    }
+    String payload = outputFile.text
+    String expectedPayload = '''
+{
+  "metadata": {
+    "runtime_name": "jvm",
+    "language_name": "jvm",
+    "runtime_version": "1.6.0_45",
+    "language_version": "1.6.0_45",
+    "tracer_version": "1.50"
+  },
+  "points": [
+    {
+      "name": "library_entrypoint.abort",
+      "tags": [
+        "reason:incompatible_runtime"
+      ]
+    }
+  ]
+'''.replaceAll(/\s+/, '')
+    payload.contains(expectedPayload)
+  }
+}

From 99abf9957f8d8351c65a2906649a53ee219e4474 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Fri, 23 May 2025 10:58:07 -0400
Subject: [PATCH 04/14] Refactored build.gradle to reuse existing functions.

---
 dd-java-agent/build.gradle                    | 25 ++++++++-----------
 .../trace/bootstrap/AgentPreCheckTest.groovy  |  5 +++-
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/dd-java-agent/build.gradle b/dd-java-agent/build.gradle
index 1c005f0f77b..7d57d72b335 100644
--- a/dd-java-agent/build.gradle
+++ b/dd-java-agent/build.gradle
@@ -17,31 +17,28 @@ configurations {
   traceShadowInclude
 }
 
-// The special pre-check should be compiled with Java 6 to detect unsupported Java versions and
-// prevent issues for users that still using them.
+// The special pre-check should be compiled with Java 6 to detect unsupported Java versions
+// and prevent issues for users that still using them.
 sourceSets {
-  java6 {
-    java {
-      srcDirs = ['src/main/java6']
-    }
+  "main_java6" {
+    java.srcDirs "${project.projectDir}/src/main/java6"
   }
 }
 
-tasks.register('compileJava6', JavaCompile) {
-  classpath = sourceSets.main.compileClasspath
-  source = sourceSets.java6.java
-  destinationDirectory = layout.buildDirectory.dir("classes/java/main")
+compileMain_java6Java.configure {
+  setJavaVersion(it, 8)
   sourceCompatibility = JavaVersion.VERSION_1_6
   targetCompatibility = JavaVersion.VERSION_1_6
+  destinationDirectory = layout.buildDirectory.dir("classes/java/main")
 }
 
+tasks.compileJava.dependsOn compileMain_java6Java
+
 dependencies {
-  java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
-  testImplementation sourceSets.java6.output
+  main_java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
+  testImplementation sourceSets.main_java6.output
 }
 
-tasks.compileJava.dependsOn compileJava6
-
 /*
  * Several shadow jars are created
  * - The main "dd-java-agent" jar that also has the bootstrap project
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index a8b3c2897c2..191b4788347 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -106,17 +106,18 @@ class AgentPreCheckTest extends Specification {
       'echo "$1	$(cat -)" >>' + outputFile.getAbsolutePath(),
       ''
     ]
-
     forwarderFile << script.join('\n')
 
     when:
     AgentPreCheck.sendTelemetry(forwarderPath, '1.6.0_45', '1.50')
 
     then:
+    // Await completion of the external process handling the payload.
     new PollingConditions().within(5) {
       assert outputFile.exists()
     }
     String payload = outputFile.text
+
     String expectedPayload = '''
 {
   "metadata": {
@@ -135,6 +136,8 @@ class AgentPreCheckTest extends Specification {
     }
   ]
 '''.replaceAll(/\s+/, '')
+
+    // Assert that the actual payload contains the expected data.
     payload.contains(expectedPayload)
   }
 }

From 2eb2753eef16d425bb41e8171c9b74ff279adbf7 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Fri, 23 May 2025 11:11:10 -0400
Subject: [PATCH 05/14] Minor cleanup.

---
 .../trace/bootstrap/AgentPreCheck.java        | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index 64fd8644af7..931679e04f7 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -11,8 +11,6 @@
 
 /** Special lightweight pre-main class that skips installation on incompatible JVMs. */
 public class AgentPreCheck {
-  public static final String AGENT_BOOTSTRAP_CLASS = "datadog.trace.bootstrap.AgentBootstrap";
-
   public static void premain(final String agentArgs, final Instrumentation inst) {
     agentmain(agentArgs, inst);
   }
@@ -20,7 +18,7 @@ public static void premain(final String agentArgs, final Instrumentation inst) {
   public static void agentmain(final String agentArgs, final Instrumentation inst) {
     try {
       if (compatible()) {
-        agentBootstrapPreMain(agentArgs, inst);
+        continueBootstrap(agentArgs, inst);
       }
     } catch (Throwable e) {
       // If agent failed we should not fail the application.
@@ -146,16 +144,11 @@ private static String getAgentVersion() {
     }
   }
 
-  @SuppressForbidden
-  private static void agentBootstrapPreMain(final String agentArgs, final Instrumentation inst) {
-    try {
-      Class<?> clazz = Class.forName(AGENT_BOOTSTRAP_CLASS);
-      Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
-      agentMain.invoke(null, agentArgs, inst);
-    } catch (Throwable e) {
-      System.err.printf(
-          "Failed to execute %s.agentmain(): %s%n", AGENT_BOOTSTRAP_CLASS, e.getMessage());
-    }
+  private static void continueBootstrap(final String agentArgs, final Instrumentation inst)
+      throws Exception {
+    Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");
+    Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
+    agentMain.invoke(null, agentArgs, inst);
   }
 
   public static final class ForwarderJsonSenderThread extends Thread {

From 0c2e81720999b66e0a6465a41e03f85237ef1753 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Fri, 23 May 2025 11:28:06 -0400
Subject: [PATCH 06/14] Added missing `@SuppressForbidden`.

---
 .../src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java  | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index 931679e04f7..c2c8b971c2c 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -15,6 +15,7 @@ public static void premain(final String agentArgs, final Instrumentation inst) {
     agentmain(agentArgs, inst);
   }
 
+  @SuppressForbidden
   public static void agentmain(final String agentArgs, final Instrumentation inst) {
     try {
       if (compatible()) {
@@ -144,6 +145,7 @@ private static String getAgentVersion() {
     }
   }
 
+  @SuppressForbidden
   private static void continueBootstrap(final String agentArgs, final Instrumentation inst)
       throws Exception {
     Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");
@@ -162,6 +164,7 @@ public ForwarderJsonSenderThread(String forwarderPath, String payload) {
       this.payload = payload;
     }
 
+    @SuppressForbidden
     @Override
     public void run() {
       ProcessBuilder builder = new ProcessBuilder(forwarderPath, "library_entrypoint");

From ea5bea7f5ede575c999aa06050443dbb97e5bf9e Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Fri, 23 May 2025 16:56:30 -0400
Subject: [PATCH 07/14] Added 'java.home' to warning. That would help to
 identify problematic JVM.

---
 dd-java-agent/build.gradle                    |  2 +-
 .../trace/bootstrap/AgentPreCheck.java        | 27 +++++++++++++++----
 .../trace/bootstrap/AgentPreCheckTest.groovy  |  4 +--
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/dd-java-agent/build.gradle b/dd-java-agent/build.gradle
index 7d57d72b335..84a0ec81bd6 100644
--- a/dd-java-agent/build.gradle
+++ b/dd-java-agent/build.gradle
@@ -35,7 +35,7 @@ compileMain_java6Java.configure {
 tasks.compileJava.dependsOn compileMain_java6Java
 
 dependencies {
-  main_java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
+  main_java6CompileOnly 'de.thetaphi:forbiddenapis:3.8'
   testImplementation sourceSets.main_java6.output
 }
 
diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index c2c8b971c2c..a027b75d50f 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -29,13 +29,19 @@ public static void agentmain(final String agentArgs, final Instrumentation inst)
   }
 
   private static void reportIncompatibleJava(
-      String javaVersion, int majorJavaVersion, String agentVersion, PrintStream output) {
+      String javaVersion,
+      int majorJavaVersion,
+      String javaHome,
+      String agentVersion,
+      PrintStream output) {
     output.println(
         "Warning: "
             + (agentVersion == null ? "This version" : "Version " + agentVersion)
             + " of dd-java-agent is not compatible with Java "
             + javaVersion
-            + " and will not be installed.");
+            + " in '"
+            + javaHome
+            + "' and will not be installed.");
 
     String msg = "Please upgrade your Java version to 8+";
     if (majorJavaVersion == 7) {
@@ -71,13 +77,24 @@ static void sendTelemetry(String forwarderPath, String javaVersion, String agent
     t.start();
   }
 
+  private static String tryGetProperty(String property) {
+    try {
+      return System.getProperty(property);
+    } catch (SecurityException e) {
+      return null;
+    }
+  }
+
   @SuppressForbidden
   private static boolean compatible() {
-    return compatible(System.getProperty("java.version"), System.err);
+    String javaVersion = tryGetProperty("java.version");
+    String javaHome = tryGetProperty("java.home");
+
+    return compatible(javaVersion, javaHome, System.err);
   }
 
   // Reachable for testing
-  static boolean compatible(String javaVersion, PrintStream output) {
+  static boolean compatible(String javaVersion, String javaHome, PrintStream output) {
     int majorJavaVersion = parseJavaMajorVersion(javaVersion);
 
     if (majorJavaVersion >= 8) {
@@ -86,7 +103,7 @@ static boolean compatible(String javaVersion, PrintStream output) {
 
     String agentVersion = getAgentVersion();
 
-    reportIncompatibleJava(javaVersion, majorJavaVersion, agentVersion, output);
+    reportIncompatibleJava(javaVersion, majorJavaVersion, javaHome, agentVersion, output);
 
     String forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
     if (forwarderPath != null) {
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index 191b4788347..7e97c8b20d9 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -61,7 +61,7 @@ class AgentPreCheckTest extends Specification {
     def logStream = new PrintStream(output)
 
     when:
-    boolean compatible = AgentPreCheck.compatible(javaVersion, logStream)
+    boolean compatible = AgentPreCheck.compatible(javaVersion, "/Library/$javaVersion", logStream)
     String log = output.toString()
     def logLines = log.isEmpty() ? [] : Arrays.asList(log.split('\n'))
 
@@ -73,7 +73,7 @@ class AgentPreCheckTest extends Specification {
     } else {
       logLines.size() == 2
       def expectedLogLines = [
-        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java ${javaVersion} and will not be installed.",
+        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion in '/Library/$javaVersion' and will not be installed.",
         "Please upgrade your Java version to 8+" + (AgentPreCheck.parseJavaMajorVersion(javaVersion) == 7 ? " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0" : "")
       ]
       assert logLines == expectedLogLines

From 9238f7da418220c5dcb826c66c1c144c1ac92e48 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Sat, 24 May 2025 10:44:04 -0400
Subject: [PATCH 08/14] Added test to ensure Java 6 & 8 compilation.

---
 .../trace/bootstrap/AgentPreCheck.java        |  2 +-
 .../trace/bootstrap/AgentPreCheckTest.groovy  | 25 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index a027b75d50f..926778e9647 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -39,7 +39,7 @@ private static void reportIncompatibleJava(
             + (agentVersion == null ? "This version" : "Version " + agentVersion)
             + " of dd-java-agent is not compatible with Java "
             + javaVersion
-            + " in '"
+            + " found at '"
             + javaHome
             + "' and will not be installed.");
 
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index 7e97c8b20d9..6acb4bf2d57 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -73,7 +73,7 @@ class AgentPreCheckTest extends Specification {
     } else {
       logLines.size() == 2
       def expectedLogLines = [
-        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion in '/Library/$javaVersion' and will not be installed.",
+        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion found at '/Library/$javaVersion' and will not be installed.",
         "Please upgrade your Java version to 8+" + (AgentPreCheck.parseJavaMajorVersion(javaVersion) == 7 ? " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0" : "")
       ]
       assert logLines == expectedLogLines
@@ -140,4 +140,27 @@ class AgentPreCheckTest extends Specification {
     // Assert that the actual payload contains the expected data.
     payload.contains(expectedPayload)
   }
+
+  private DataInputStream classStream(Class clazz) {
+    String resource = clazz.getName().replace('.', '/') + '.class'
+    new DataInputStream(this.getClass().getClassLoader().getResourceAsStream(resource))
+  }
+
+  def 'check #clazz compiled with Java #javaVersion'() {
+    expect:
+    classStream(clazz).withCloseable { stream ->
+      def magic = Integer.toUnsignedLong(stream.readInt())
+      def minor = (int) stream.readShort()
+      def major = (int) stream.readShort()
+
+      magic == 0xCAFEBABEL
+      minor == 0
+      major == expectedMajor
+    }
+
+    where:
+    clazz          | javaVersion | expectedMajor
+    AgentPreCheck  | 6           | 50
+    AgentBootstrap | 8           | 52
+  }
 }

From 5f61b621e070192f00900500e4991b7b2c93deb6 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Sat, 24 May 2025 12:02:35 -0400
Subject: [PATCH 09/14] Fixed test.

---
 .../trace/bootstrap/AgentPreCheckTest.groovy  | 27 +++++++++----------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index 6acb4bf2d57..1828eb40e74 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -141,22 +141,21 @@ class AgentPreCheckTest extends Specification {
     payload.contains(expectedPayload)
   }
 
-  private DataInputStream classStream(Class clazz) {
-    String resource = clazz.getName().replace('.', '/') + '.class'
-    new DataInputStream(this.getClass().getClassLoader().getResourceAsStream(resource))
-  }
-
   def 'check #clazz compiled with Java #javaVersion'() {
+    setup:
+    def resource = clazz.getName().replace('.', '/') + '.class'
+    def stream = new DataInputStream(this.getClass().getClassLoader().getResourceAsStream(resource))
+
     expect:
-    classStream(clazz).withCloseable { stream ->
-      def magic = Integer.toUnsignedLong(stream.readInt())
-      def minor = (int) stream.readShort()
-      def major = (int) stream.readShort()
-
-      magic == 0xCAFEBABEL
-      minor == 0
-      major == expectedMajor
-    }
+    stream.withCloseable {
+      def magic = Integer.toUnsignedLong(it.readInt())
+      def minor = (int) it.readShort()
+      def major = (int) it.readShort()
+
+      assert magic == 0xCAFEBABE
+      assert minor == 0
+      assert major == expectedMajor
+    } == null
 
     where:
     clazz          | javaVersion | expectedMajor

From 5fa1bb6beca605e70c7c23978bc3d3714ab4d1fb Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Tue, 27 May 2025 13:26:35 -0400
Subject: [PATCH 10/14] Drop support for 0.x version.

---
 .../datadog/trace/bootstrap/AgentPreCheck.java   | 16 +++-------------
 .../trace/bootstrap/AgentPreCheckTest.groovy     |  4 ++--
 .../src/test/java/StartWithAgentTest.java        |  2 +-
 3 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index 926778e9647..f4d57338311 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -29,11 +29,7 @@ public static void agentmain(final String agentArgs, final Instrumentation inst)
   }
 
   private static void reportIncompatibleJava(
-      String javaVersion,
-      int majorJavaVersion,
-      String javaHome,
-      String agentVersion,
-      PrintStream output) {
+      String javaVersion, String javaHome, String agentVersion, PrintStream output) {
     output.println(
         "Warning: "
             + (agentVersion == null ? "This version" : "Version " + agentVersion)
@@ -42,13 +38,7 @@ private static void reportIncompatibleJava(
             + " found at '"
             + javaHome
             + "' and will not be installed.");
-
-    String msg = "Please upgrade your Java version to 8+";
-    if (majorJavaVersion == 7) {
-      msg +=
-          " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0";
-    }
-    output.println(msg);
+    output.println("Please upgrade your Java version to 8+");
   }
 
   static void sendTelemetry(String forwarderPath, String javaVersion, String agentVersion) {
@@ -103,7 +93,7 @@ static boolean compatible(String javaVersion, String javaHome, PrintStream outpu
 
     String agentVersion = getAgentVersion();
 
-    reportIncompatibleJava(javaVersion, majorJavaVersion, javaHome, agentVersion, output);
+    reportIncompatibleJava(javaVersion, javaHome, agentVersion, output);
 
     String forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
     if (forwarderPath != null) {
diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index 1828eb40e74..01c8d73b9e2 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -74,7 +74,7 @@ class AgentPreCheckTest extends Specification {
       logLines.size() == 2
       def expectedLogLines = [
         "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion found at '/Library/$javaVersion' and will not be installed.",
-        "Please upgrade your Java version to 8+" + (AgentPreCheck.parseJavaMajorVersion(javaVersion) == 7 ? " or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0" : "")
+        "Please upgrade your Java version to 8+"
       ]
       assert logLines == expectedLogLines
     }
@@ -152,7 +152,7 @@ class AgentPreCheckTest extends Specification {
       def minor = (int) it.readShort()
       def major = (int) it.readShort()
 
-      assert magic == 0xCAFEBABE
+      assert magic == 0xCAFEBABEL
       assert minor == 0
       assert major == expectedMajor
     } == null
diff --git a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
index b9acd13cb51..9b07e20ba97 100644
--- a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
+++ b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
@@ -15,7 +15,7 @@
 public class StartWithAgentTest {
 
   private static final Pattern WARNING_PATTERN = Pattern.compile("^Warning: Version [^ ]+ of dd-java-agent is not compatible with Java [^ ]+ and will not be installed\\.$");
-  private static final String UPGRADE_MESSAGE = "Please upgrade your Java version to 8+ or use the 0.x version of dd-java-agent in your build tool or download it from https://dtdg.co/java-tracer-v0";
+  private static final String UPGRADE_MESSAGE = "Please upgrade your Java version to 8+";
 
   @Test
   void ensureThatApplicationStartsWithAgentOnJava7() throws InterruptedException, IOException {

From be58d6bcd91015a4aacb308de74ecb7110538754 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Tue, 27 May 2025 15:24:06 -0400
Subject: [PATCH 11/14] Fixed small typo.

---
 .../groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index 01c8d73b9e2..ea726ece99b 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -8,7 +8,7 @@ import java.nio.file.Path
 import java.nio.file.attribute.PosixFilePermissions
 
 class AgentPreCheckTest extends Specification {
-  def 'parse java.version of #versionƒ as #expected'() {
+  def 'parse java.version of #version as #expected'() {
     when:
     def major = AgentPreCheck.parseJavaMajorVersion(version)
 

From 7c2a597f88229970f68085c8347565e23fcb2af0 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Tue, 27 May 2025 17:10:35 -0400
Subject: [PATCH 12/14] Fixed test.

---
 .../agent-logs-on-java-7/src/test/java/StartWithAgentTest.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
index 9b07e20ba97..7b54e50c233 100644
--- a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
+++ b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
@@ -14,7 +14,7 @@
 
 public class StartWithAgentTest {
 
-  private static final Pattern WARNING_PATTERN = Pattern.compile("^Warning: Version [^ ]+ of dd-java-agent is not compatible with Java [^ ]+ and will not be installed\\.$");
+  private static final Pattern WARNING_PATTERN = Pattern.compile("^Warning: Version [^ ]+ of dd-java-agent is not compatible with Java [^ ]+ found at [^ ]+ and will not be installed\\.$");
   private static final String UPGRADE_MESSAGE = "Please upgrade your Java version to 8+";
 
   @Test

From 8192ac413aee60b614a2d4c0bd939f9a0c7de9ec Mon Sep 17 00:00:00 2001
From: Alexey <alexey.kuznetsov@datadoghq.com>
Date: Wed, 28 May 2025 10:30:24 -0400
Subject: [PATCH 13/14] Update
 dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java

Co-authored-by: Brice Dutheil <brice.dutheil@gmail.com>
---
 .../src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
index f4d57338311..a2919226eb5 100644
--- a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
+++ b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentPreCheck.java
@@ -37,7 +37,7 @@ private static void reportIncompatibleJava(
             + javaVersion
             + " found at '"
             + javaHome
-            + "' and will not be installed.");
+            + "' and is effectively disabled.");
     output.println("Please upgrade your Java version to 8+");
   }
 

From e1df6fe273fbbcc9c7d772280d03ce89789dbde4 Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <alexey.kuznetsov@datadoghq.com>
Date: Wed, 28 May 2025 10:37:23 -0400
Subject: [PATCH 14/14] Fixed test.

---
 .../groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy     | 2 +-
 .../agent-logs-on-java-7/src/test/java/StartWithAgentTest.java  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
index ea726ece99b..e67614813b5 100644
--- a/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
+++ b/dd-java-agent/src/test/groovy/datadog/trace/bootstrap/AgentPreCheckTest.groovy
@@ -73,7 +73,7 @@ class AgentPreCheckTest extends Specification {
     } else {
       logLines.size() == 2
       def expectedLogLines = [
-        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion found at '/Library/$javaVersion' and will not be installed.",
+        "Warning: Version ${AgentJar.getAgentVersion()} of dd-java-agent is not compatible with Java $javaVersion found at '/Library/$javaVersion' and is effectively disabled.",
         "Please upgrade your Java version to 8+"
       ]
       assert logLines == expectedLogLines
diff --git a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
index 7b54e50c233..b354b5e30e0 100644
--- a/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
+++ b/test-published-dependencies/agent-logs-on-java-7/src/test/java/StartWithAgentTest.java
@@ -14,7 +14,7 @@
 
 public class StartWithAgentTest {
 
-  private static final Pattern WARNING_PATTERN = Pattern.compile("^Warning: Version [^ ]+ of dd-java-agent is not compatible with Java [^ ]+ found at [^ ]+ and will not be installed\\.$");
+  private static final Pattern WARNING_PATTERN = Pattern.compile("^Warning: Version [^ ]+ of dd-java-agent is not compatible with Java [^ ]+ found at [^ ]+ and is effectively disabled\\.$");
   private static final String UPGRADE_MESSAGE = "Please upgrade your Java version to 8+";
 
   @Test