Key Serializer caching test

results.txt

junit.framework.ComparisonFailure: null 
Expected :{"map":{"Karl":1}}
Actual   :{"map":{"Not Karl":1}}
 <Click to see difference>
	at TestKeySerializer.TestBoth(TestKeySerializer.java:42)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:76)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:195)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:63)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)


Process finished with exit code 255

TestKeySerializer.java

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.google.common.collect.ImmutableMap;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.util.Map;

import static junit.framework.Assert.assertEquals;

public class TestKeySerializer {

    private ObjectMapper mapper;

    @Before
    public void setUp()
    {
        mapper = new ObjectMapper();
    }

    @Test
    public void TestNotKarl() throws IOException {
        final String serialized = mapper.writeValueAsString(new NotKarlBean());
        assertEquals("{\"map\":{\"Not Karl\":1}}", serialized);
    }

    @Test
    public void TestKarl() throws IOException {
        final String serialized = mapper.writeValueAsString(new KarlBean());
        assertEquals("{\"map\":{\"Karl\":1}}", serialized);
    }

    @Test
    public void TestBoth() throws IOException {
        final String value1 = mapper.writeValueAsString(new NotKarlBean());
        final String value2 = mapper.writeValueAsString(new KarlBean());
        assertEquals("{\"map\":{\"Not Karl\":1}}", value1);
        assertEquals("{\"map\":{\"Karl\":1}}", value2);
    }

    public static class KarlSerializer extends JsonSerializer<String>
    {
        @Override
        public void serialize(String value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
            jgen.writeFieldName("Karl");
        }
    }

    public static class NotKarlBean
    {
        public Map<String,Integer> map = ImmutableMap.of("Not Karl", 1);
    }

    public static class KarlBean
    {
        @JsonSerialize(keyUsing = KarlSerializer.class)
        public Map<String,Integer> map = ImmutableMap.of("Not Karl", 1);
    }

}

Hmmh. Is it just me or is KarlBean bit buggy, wrt value contained?