Example of NPE when using 'pretty' query parameter with ElasticSearch 0.90.6

gistfile1.java

import org.elasticsearch.client.Client;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.RestChannel;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.rest.XContentRestResponse;
import org.elasticsearch.rest.action.support.RestXContentBuilder;

public class DummyAction extends BaseRestHandler {

    @Inject
    protected DummyAction(Settings settings, Client client, RestController controller) {
        super(settings, client);
        controller.registerHandler(RestRequest.Method.GET, "/junk", this);
    }

    @Override
    public void handleRequest(final RestRequest request, final RestChannel channel) {
        try {
            XContentBuilder builder = RestXContentBuilder.restContentBuilder(request).startObject();
            builder.field("foo", "bar");
            builder.endObject().close(); // closing the builder is what causes the NPE
            channel.sendResponse(new XContentRestResponse(request, RestStatus.OK, builder));
        }
        catch (Exception e) {
            logger.error("error", e);
        }
    }
}

gistfile2.txt

curl -XGET localhost:9200/junk?pretty

gistfile3.txt

[2013-11-05 15:41:59,475][ERROR][com.donkey.DummyAction] [Blitzschlag, Baron Von] error
java.lang.NullPointerException
	at java.lang.System.arraycopy(Native Method)
	at org.elasticsearch.common.jackson.core.json.UTF8JsonGenerator._writeBytes(UTF8JsonGenerator.java:1125)
	at org.elasticsearch.common.jackson.core.json.UTF8JsonGenerator.writeRaw(UTF8JsonGenerator.java:603)
	at org.elasticsearch.common.xcontent.json.JsonXContentGenerator.close(JsonXContentGenerator.java:332)
	at org.elasticsearch.common.xcontent.XContentBuilder.close(XContentBuilder.java:1051)
	at org.elasticsearch.common.xcontent.XContentBuilder.bytes(XContentBuilder.java:1067)
	at org.elasticsearch.http.netty.NettyHttpChannel.sendResponse(NettyHttpChannel.java:111)
	at com.donkey.DummyAction.handleRequest(DummyAction.java:29)
	at org.elasticsearch.rest.RestController.executeHandler(RestController.java:159)
	at org.elasticsearch.rest.RestController.dispatchRequest(RestController.java:142)
	at org.elasticsearch.http.HttpServer.internalDispatchRequest(HttpServer.java:121)
	at org.elasticsearch.http.HttpServer$Dispatcher.dispatchRequest(HttpServer.java:83)
	at org.elasticsearch.http.netty.NettyHttpServerTransport.dispatchRequest(NettyHttpServerTransport.java:291)
	at org.elasticsearch.http.netty.HttpRequestHandler.messageReceived(HttpRequestHandler.java:43)
	at org.elasticsearch.common.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
	at org.elasticsearch.common.netty.handler.codec.http.HttpChunkAggregator.messageReceived(HttpChunkAggregator.java:145)
	at org.elasticsearch.common.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
	at org.elasticsearch.common.netty.channel.Channels.fireMessageReceived(Channels.java:296)
	at org.elasticsearch.common.netty.handler.codec.frame.FrameDecoder.unfoldAndFireMessageReceived(FrameDecoder.java:459)
	at org.elasticsearch.common.netty.handler.codec.replay.ReplayingDecoder.callDecode(ReplayingDecoder.java:536)
	at org.elasticsearch.common.netty.handler.codec.replay.ReplayingDecoder.messageReceived(ReplayingDecoder.java:435)
	at org.elasticsearch.common.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
	at org.elasticsearch.common.netty.OpenChannelsHandler.handleUpstream(OpenChannelsHandler.java:74)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
	at org.elasticsearch.common.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)
	at org.elasticsearch.common.netty.channel.Channels.fireMessageReceived(Channels.java:268)
	at org.elasticsearch.common.netty.channel.Channels.fireMessageReceived(Channels.java:255)
	at org.elasticsearch.common.netty.channel.socket.nio.NioWorker.read(NioWorker.java:88)
	at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:109)
	at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:312)
	at org.elasticsearch.common.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:90)
	at org.elasticsearch.common.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
	at org.elasticsearch.common.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
	at org.elasticsearch.common.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:695)