Exception in thread "main" java.lang.NoClassDefFoundError: graphics/shapes/Square
    at Main.main(Main.java:7)
Caused by: java.lang.ClassNotFoundException: graphics.shapes.Square
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 1 more

graphics
├ Main.java
├ shapes
|   ├ Square.java
|   ├ Triangle.java
├ linepoint
|   ├ Line.java
|   ├ Point.java
├ spaceobjects
|   ├ Cube.java
|   ├ RectPrism.java

import graphics.shapes.*;
import graphics.linepoint.*
import graphics.spaceobjects.*;

public class Main {
    public static void main(String args[]) {
        Square s = new Square(2,3,15);
        Line l = new Line(1,5,2,3);
        Cube c = new Cube(13,32,22);
    }
}

On Compiling process use this command:

javac -d . [FileName.java]

To Run the class please use this command:

java [Package].[ClassName]

java.lang.NoClassDefFoundError

public class ClassA{
public static void main(String args[]){
     //Some gibberish Code...
     String text = ClassB.getString();
     System.out.println("Text is :" + text);
}

public class ClassB{
    public static String getString(){
      return "Testing Some Exception";
 }
}

cd out
java -classpath . com.blahcode.Main

// ClassLoaderTracer.java
// From: https://blogs.oracle.com/sundararajan/entry/tracing_class_loading_1_5

import java.lang.instrument.*;
import java.security.*;

// manifest.mf
// Premain-Class: ClassLoadTracer

// jar -cvfm tracer.jar manifest.mf ClassLoaderTracer.class

// java -javaagent:tracer.jar  [...]

public class ClassLoadTracer
{
    public static void premain(String agentArgs, Instrumentation inst)
    {
        final java.io.PrintStream out = System.out;
        inst.addTransformer(new ClassFileTransformer() {
            public byte[] transform(ClassLoader loader, String className, Class classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {

                String pd = (null == protectionDomain) ? "null" : protectionDomain.getCodeSource().toString();
                out.println(className + " loaded by " + loader + " at " + new java.util.Date() + " in " + pd);

                // dump stack trace of the thread loading class
                Thread.dumpStack();

                // we just want the original .class bytes to be loaded!
                // we are not instrumenting it...
                return null;
            }
        });
    }
}

public class MyClass{
       private static  Handler mHandler = new Handler();
       public static int num = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //test code start
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                MyClass myClass = new MyClass();
            } catch (Throwable e) {
                e.printStackTrace();
            }
        }
    }).start();

    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    MyClass.num = 3;
    // end of test code
}

private static Handler mHandler;
private static HandlerThread handlerThread = new HandlerThread("newthread");
static {
    handlerThread.start();
    mHandler = new Handler(handlerThread.getLooper(), mHandlerCB);
}

compile 'com.google.android.gms:play-services-gcm:11.0.4'
compile 'com.google.android.gms:play-services:11.0.4'

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
})
compile files('libs/ypylibs.jar')
compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.google.android.gms:play-services-gcm:11.0.4'
compile 'com.google.android.gms:play-services:11.0.4'
compile 'com.google.android.gms:play-services-ads:11.0.4'
compile 'com.dailymotion.dailymotion-sdk-android:sdk:0.1.12'
compile 'org.apache.httpcomponents:httpcore:4.4.1'
compile 'commons-io:commons-io:1.3.2'
compile 'com.oguzdev:CircularFloatingActionMenu:1.0.2'
compile 'com.android.support:multidex:1.0.1'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'