ARROW-1817: [Java] Configure JsonReader to read floating point NaN values

java/vector/src/main/java/org/apache/arrow/vector/ipc/JsonFileReader.java

@@ -69,6 +69,8 @@ public JsonFileReader(File inputFile, BufferAllocator allocator) throws JsonPars
     this.allocator = allocator;
     MappingJsonFactory jsonFactory = new MappingJsonFactory();
     this.parser = jsonFactory.createParser(inputFile);
+    // Allow reading NaN for floating point values
+    this.parser.configure(JsonParser.Feature.ALLOW_NON_NUMERIC_NUMBERS, true);
   }
 
   @Override

java/vector/src/main/java/org/apache/arrow/vector/ipc/JsonFileWriter.java

@@ -84,6 +84,8 @@ public JsonFileWriter(File outputFile, JSONWriteConfig config) throws IOExceptio
       prettyPrinter.indentArraysWith(NopIndenter.instance);
       this.generator.setPrettyPrinter(prettyPrinter);
     }
+    // Allow writing of floating point NaN values not as strings
+    this.generator.configure(JsonGenerator.Feature.QUOTE_NON_NUMERIC_NUMBERS, false);
   }
 
   public void start(Schema schema, DictionaryProvider provider) throws IOException {

java/vector/src/test/java/org/apache/arrow/vector/ipc/BaseFileTest.java

@@ -47,6 +47,7 @@
 import org.apache.arrow.vector.complex.writer.BaseWriter.MapWriter;
 import org.apache.arrow.vector.complex.writer.BigIntWriter;
 import org.apache.arrow.vector.complex.writer.DateMilliWriter;
+import org.apache.arrow.vector.complex.writer.Float4Writer;
 import org.apache.arrow.vector.complex.writer.IntWriter;
 import org.apache.arrow.vector.complex.writer.TimeMilliWriter;
 import org.apache.arrow.vector.complex.writer.TimeStampMilliTZWriter;
@@ -95,10 +96,28 @@ public void tearDown() {
     DateTimeZone.setDefault(defaultTimezone);
   }
 
+  protected void writeData(int count, MapVector parent) {
+    ComplexWriter writer = new ComplexWriterImpl("root", parent);
+    MapWriter rootWriter = writer.rootAsMap();
+    IntWriter intWriter = rootWriter.integer("int");
+    BigIntWriter bigIntWriter = rootWriter.bigInt("bigInt");
+    Float4Writer float4Writer = rootWriter.float4("float");
+    for (int i = 0; i < count; i++) {
+      intWriter.setPosition(i);
+      intWriter.writeInt(i);
+      bigIntWriter.setPosition(i);
+      bigIntWriter.writeBigInt(i);
+      float4Writer.setPosition(i);
+      float4Writer.writeFloat4(i == 0 ? Float.NaN : i);
+    }
+    writer.setValueCount(count);
+  }
+
   protected void validateContent(int count, VectorSchemaRoot root) {
     for (int i = 0; i < count; i++) {
       Assert.assertEquals(i, root.getVector("int").getObject(i));
       Assert.assertEquals(Long.valueOf(i), root.getVector("bigInt").getObject(i));
+      Assert.assertEquals(i == 0 ? Float.NaN : i, root.getVector("float").getObject(i));
     }
   }
 
@@ -454,20 +473,6 @@ protected void validateDecimalData(VectorSchemaRoot root) {
     }
   }
 
-  protected void writeData(int count, MapVector parent) {
-    ComplexWriter writer = new ComplexWriterImpl("root", parent);
-    MapWriter rootWriter = writer.rootAsMap();
-    IntWriter intWriter = rootWriter.integer("int");
-    BigIntWriter bigIntWriter = rootWriter.bigInt("bigInt");
-    for (int i = 0; i < count; i++) {
-      intWriter.setPosition(i);
-      intWriter.writeInt(i);
-      bigIntWriter.setPosition(i);
-      bigIntWriter.writeBigInt(i);
-    }
-    writer.setValueCount(count);
-  }
-
   public void validateUnionData(int count, VectorSchemaRoot root) {
     FieldReader unionReader = root.getVector("union").getReader();
     for (int i = 0; i < count; i++) {

java/vector/src/test/java/org/apache/arrow/vector/ipc/TestJSONFile.java

@@ -38,6 +38,33 @@
 public class TestJSONFile extends BaseFileTest {
   private static final Logger LOGGER = LoggerFactory.getLogger(TestJSONFile.class);
 
+  @Test
+  public void testWriteRead() throws IOException {
+    File file = new File("target/mytest.json");
+    int count = COUNT;
+
+    // write
+    try (BufferAllocator originalVectorAllocator = allocator.newChildAllocator("original vectors", 0, Integer.MAX_VALUE);
+         MapVector parent = MapVector.empty("parent", originalVectorAllocator)) {
+      writeData(count, parent);
+      writeJSON(file, new VectorSchemaRoot(parent.getChild("root")), null);
+    }
+
+    // read
+    try (
+        BufferAllocator readerAllocator = allocator.newChildAllocator("reader", 0, Integer.MAX_VALUE);
+        JsonFileReader reader = new JsonFileReader(file, readerAllocator)
+    ) {
+      Schema schema = reader.start();
+      LOGGER.debug("reading schema: " + schema);
+
+      // initialize vectors
+      try (VectorSchemaRoot root = reader.read();) {
+        validateContent(count, root);
+      }
+    }
+  }
+
   @Test
   public void testWriteReadComplexJSON() throws IOException {
     File file = new File("target/mytest_complex.json");