Android studio Classnotfound Exception when trying to use Serialization to java server in eclipse

Question

I was trying to use ThreadHandler and Thread Communication in the process of using ObjectInputStream and ObjectOutputStream with a class I made called graphVariable which I have in a server that I made in java, eclipse, I think the problem is that they are not in the same package but I don't know how to make them in the same package, one in eclipse, java and one in android, I tried making a package called Objects and putting the graphVariable class in both the server and the client but it doesn't change a thing. This is the error:

08-13 14:14:56.949 17040-19174/com.example.ilan.arppcont W/System.err: java.lang.ClassNotFoundException: [LgraphVariable;
08-13 14:14:56.954 17040-19174/com.example.ilan.arppcont W/System.err:     at java.lang.Class.classForName(Native Method)
08-13 14:14:56.955 17040-19174/com.example.ilan.arppcont W/System.err:     at java.lang.Class.forName(Class.java:400)
        at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:626)
        at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1613)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1518)
        at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1664)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1345)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:373)
        at com.example.ilan.arppcont.MyThread.run(class_bitarb.java:35)
08-13 14:14:56.960 17040-19174/com.example.ilan.arppcont W/System.err: Caused by: java.lang.ClassNotFoundException: Didn't find class "graphVariable" on path: DexPathList[[zip file "/data/app/com.example.ilan.arppcont-1/base.apk"],nativeLibraryDirectories=[/data/app/com.example.ilan.arppcont-1/lib/arm64, /system/lib64, /vendor/lib64]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        ... 9 more

This is the code for the client:

package com.example.ilan.arppcont;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import ServerComm.Graph;
import ServerComm.graphVariable;

class MyThread extends Thread {
    boolean running = true;
    HandlerThread myThread = new HandlerThread("hi");
    Looper mLooper;
    @Override
    public void run(){
        if(running) {
            myThread.start();
            mLooper = myThread.getLooper();
            class_bitarb.MyHandler mHandler = new class_bitarb.MyHandler(mLooper);

            try {
                class_server.out.writeObject("update");
                while (true) {
                    graphVariable[] input = (graphVariable[]) class_server.in.readObject();
                    if (input != null) {
                        class_bitarb.graph = input;
                        break;
                    }
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            class_graph.graph = Graph.start(class_bitarb.graph, class_graph.textView);
            Message msg = Message.obtain();
            msg.obj = false;
            mHandler.sendMessage(msg);
        }
    };

    public void setRunning(boolean running) {
        this.running = running;
    }
}

public class class_bitarb extends AppCompatActivity {
    static MyThread mThread = new MyThread();
    public static class MyHandler extends Handler {
        public MyHandler(Looper myLooper) {
            super(myLooper);
        }
        public void handleMessage(Message msg) {
            mThread.setRunning(false);
        }
    }
    static Button btn_update;
    static RecyclerView list;
    static graphVariable[] graph = null;
    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_client);

        //Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        //setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        //mViewPager = (ViewPager) findViewById(R.id.container);
        //mViewPager.setAdapter(mSectionsPagerAdapter);

        //TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

        //mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        //tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));


    }

    static String input = "";
    public static void addListenerOnButton(View view) {
        btn_update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {

                mThread.start();
                Looper mLooper = mThread.mLooper;
                while(true){
                    if(mLooper!=null){
                        break;
                    }else{
                        mLooper = mThread.mLooper;
                    }
                }

                MyHandler mHandler = new MyHandler(mLooper);

            }
        });
    }


    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_bitarb, container, false);
            btn_update = (Button) rootView.findViewById(R.id.btn_update);
            list = (RecyclerView) rootView.findViewById(R.id.list);
            addListenerOnButton(rootView);
            return rootView;
        }
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a PlaceholderFragment (defined as a static inner class below).
            return PlaceholderFragment.newInstance(position + 1);
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 1;
        }
    }
}

And here is the Class:

public class graphVariable implements Serializable{
    private static final long serialVersionUID = 5830807339573412345L;
    public double x1; 
    public double y1;
    public double[] x;
    public double[] y;
    public APIs ef;
    public APIs et;
    public double ratio;
    public graphVariable() {
        x = new double[50];
        y = new double[50];
        ratio = 0;
        ef= APIs.hi;
        et= APIs.hi;
    }
}

Also, I want to point it out that I have tried lots of stuff. Here is the build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.ilan.arppcontv2"
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0-rc01'
    implementation 'com.android.support:design:28.0.0-rc01'
    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation files('libs/GraphView-4.2.1.jar')
}

But you are not pointing in any direction. Add links to what you have tried — Vivek Mishra, Aug 13 '18 at 11:23
I have tried: https://stackoverflow.com/questions/19930323/android-studio-classnotfoundexception, https://stackoverflow.com/questions/17408769/how-do-i-resolve-classnotfoundexception, https://stackoverflow.com/questions/6014806/android-classnotfoundexception-when-passing-serializable-object-to-activity, https://stackoverflow.com/questions/19523167/android-classnotfoundexception-didnt-find-class-on-path Iwould also like to point it out that maybe i did some stuff wrong when trying the answers in the links above. — Ilan, Aug 13 '18 at 11:30
you have not properly added multidex support. I think doing that properly will solve your problem. Multidex also requires a gradle dependency too. You are missing that. — Vivek Mishra, Aug 13 '18 at 11:49
It did not work, i added the implementation, i edited it in the post — Ilan, Aug 13 '18 at 11:53
what do you men application class code for multidex? sorry im a noob :D — Ilan, Aug 13 '18 at 11:56
It is super simple: this message tells you that the side that tries to *read* an array of objects of your new class ... doesn't have the .class files for that new class. Your client is **missing** your new class at runtime. Beyond that: read about java naming convents. Class names go UpperCase. Always. — GhostCat, Aug 13 '18 at 11:56
https://stackoverflow.com/questions/26609734/how-to-enable-multidexing-with-the-new-android-multidex-support-library — Vivek Mishra, Aug 13 '18 at 11:58
its in the code, i also tried moving it from folder to folder — Ilan, Aug 13 '18 at 11:58
I don't have a class that extends application, i added compile 'com.android.support:multidex:1.0.3' to the build.gradle — Ilan, Aug 13 '18 at 12:02
i have added android:name="android.support.multidex.MultiDexApplication" to the mainfest — Ilan, Aug 13 '18 at 12:12
Did you check tried configuring progaurd like in this answer https://stackoverflow.com/a/6780028/6699069 ? — sziraqui, Aug 15 '18 at 16:48

score 0 · Accepted Answer · answered Aug 21 '18 at 13:50

0

Use JSON for all communications, it doesn't use serialization, should solve your problem.

answered Aug 21 '18 at 13:50

Yocttar

16

good answer! it works but i wonder if there are any other ways. – Ilan Aug 21 '18 at 13:53

Android studio Classnotfound Exception when trying to use Serialization to java server in eclipse

1 Answers1