asked on

Java Json

I am trying to make a very basic parsing of this Json but I am getting strange error messages.

import com.google.gson.Gson;
import com.google.gson.JsonParser;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import java.util.List;


public class json
{
    public static void main(String[] args)
    {
        
        String line = "{\"handlerService\":\"ORIGINATION_XX\",\"type\":\"DLV\",\"srcAddress\":{\"pin\":\"D4AAAABC\",\"guid\":\"XXY_P2P\",\"suid\":null,\"endPointType\":\"PIN\",\"serverMessage\":false},\"destinationCount\":1,\"dstAddresses\":{\"pin\":\"da888111\",\"guid\":null,\"suid\":null,\"endPointType\":\"PIN\",\"serverMessage\":false},\"source\":\"UNKNOWN\",\"userAgent\":null,\"nextHop\":\"\",\"msgStatus\":\"RESPONSE_SENT\",\"msgId\":\"14419ASF93\",\"callId\":\"1basfdsf925771d032aa3e81895037@10.132.22.129\",\"country\":\"UNKNOWN\",\"logVersion\":\"1.0\",\"sipStatus\":200,\"gmeError\":0,\"deliveryInfoRequired\":0,\"payloadInfo\":{\"contentLength\":0,\"appType\":\"0\",\"appSubType\":\"0\",\"contentId\":\"ABB_IM\"}}";
        System.out.println(line);
        JsonElement jelement = new JsonParser().parse(line);
        JsonObject  jobject  = jelement.getAsJsonObject();
        jobject              = jobject.getAsJsonObject("srcAddress");
        String result = jobject.get("pin").toString();
        System.out.println(result);
    }
}

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There is no compile time error message.

On run time this is what I get.

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/gson/JsonParser
	at json.main(json.java:15)
Caused by: java.lang.ClassNotFoundException: com.google.gson.JsonParser
	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
	... 1 more

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What am I doing wrong?

CEHJ

You're failing to use the same classpath for running as for compiling

farzanj

ASKER

I am compiling using this command:

javac  -classpath ./google-gson-2.2.4/gson-2.2.4.jar json

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And then running using

java  -classpath ./google-gson-2.2.4/gson-2.2.4.jar json

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And get the error message like:

Exception in thread "main" java.lang.NoClassDefFoundError: json
Caused by: java.lang.ClassNotFoundException: json
	at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: json.  Program will exit.

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BTW, I am using Linux.

farzanj

ASKER

My follow up questions would be:

1. How do I deploy it?
2. Can I make these libraries a part of object code so that I don't need to mention it using -classlib syntax?
3. Typically in C++ in order to deploy I either provide a Makefile sometimes configure or even RPM. What is the standard way to deploy a Java application? Are there shared libraries sometimes?

CEHJ

javac  -classpath ./google-gson-2.2.4/gson-2.2.4.jar json

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should be

javac  -classpath ./google-gson-2.2.4/gson-2.2.4.jar json.java

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farzanj

ASKER

Yes, it is just a typo in my question. I have this.

It is compiling fine. If I had missed .java, it would complain that the file is not found.

In any case, when I run it, I still get error messages as shown above.

farzanj

ASKER

Just copied from the console:

$ javac -classpath ./google-gson-2.2.4/gson-2.2.4.jar json.java
$ java -cp google-gson-2.2.4/gson-2.2.4.jar json
Exception in thread "main" java.lang.NoClassDefFoundError: json
Caused by: java.lang.ClassNotFoundException: json
      at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: json. Program will exit.

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CEHJ

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farzanj

ASKER

Ok, yes that works. Reason?

Also please address the questions in 39351008

CEHJ

The reason is that you missed a path (the current directory, which contains json.class [incidentally classnames in Java should begin upper case]) out of the classpath

To answer your other questions, i'd need to know the purpose of your code. Currently it looks like a fragment of something else

farzanj

ASKER

Right now I am writing for Hadoop that would run on Linux server. I haven't used Java for a long time but I have to get back to it because Hadoop is Java oriented. But in general as well, I need to know the best practices of delivering Java code for, say, servers and for web work or even desktop.

For Hadoop I think the answer is creating executable Jar but I need the syntax for that as well.

CEHJ

An executable jar is a good start - it's the basis of many different scenarios

http://www.mkyong.com/java/how-to-make-an-executable-jar-file/

Bear in mind that, if want to use the resulting jar as an executable jar (no classpath specified by the 'user') you need to use the Class-Path attribute in the manifest for all dependencies

farzanj

ASKER

Thanks