title: java.lang.IllegalArgumentException: class java.text.DecimalFormat declares multiple JSON fields named maximumIntegerDigits
body: <p>I am making an ajax call to the servlet. I want the data back from the servlet to the jsp:</p>
  
  <pre><code>PrintWriter out = response.getWriter();
      String isbn = (String) request.getParameter("isbn");
      BookDetail bd = new BookDetail();
      if(bd.ISBNFound(isbn)){
      ArrayList&lt;KitapData&gt; Books = bd.LoadBooksByISBN(isbn);
  
      Gson gson = new Gson();
      String json = gson.toJson(Books);
      response.setContentType("application/json");
      System.out.print(json);      
      out.print(json);
  }
  </code></pre>
  
  <p>I've added the GSon.jar in the classpath. But Iam getting some error: Complete list is as follows: What am i missing here?</p>
  
  <pre><code>WARNING:   StandardWrapperValve[Book_CheckISBN]: Servlet.service() for servlet Book_CheckISBN threw exception
  java.lang.IllegalArgumentException: class java.text.DecimalFormat declares multiple JSON fields named maximumIntegerDigits
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:122)
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
      at com.google.gson.Gson.getAdapter(Gson.java:356)
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.&lt;init&gt;(ReflectiveTypeAdapterFactory.java:82)
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:81)
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:118)
      at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
      at com.google.gson.Gson.getAdapter(Gson.java:356)
      at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:55)
      at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
      at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
      at com.google.gson.Gson.toJson(Gson.java:593)
      at com.google.gson.Gson.toJson(Gson.java:572)
      at com.google.gson.Gson.toJson(Gson.java:527)
      at com.google.gson.Gson.toJson(Gson.java:507)
      at book.ctrl.Book_CheckISBN.doPost(Book_CheckISBN.java:41)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
      at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
      at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
      at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
      at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
      at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282)
      at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
      at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
      at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201)
      at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175)
      at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
      at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
      at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
      at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
      at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
      at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
      at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
      at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561)
      at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
      at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
      at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
      at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
      at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
      at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
      at java.lang.Thread.run(Thread.java:722)
  </code></pre>