package com.test.app;
 
import com.unity3d.player.UnityPlayerActivity;
import android.content.Context;
import android.os.Bundle;
import android.util.Config;
import android.util.Log;
public class PluginTest extends UnityPlayerActivity
{
    private static final String TAG = "PluginTest_Unity";
    private static int number = 0;
 
    @Override
    protected void onCreate(Bundle myBundle) {
        super.onCreate(myBundle);
 
    }
    @Override
    protected void onResume() {
        if (Config.DEBUG)
            Log.d(TAG, "onResume");
        super.onResume();
    }
    @Override
    protected void onPause()
    {
        super.onPause();
    }
    @Override
    protected void onStop() {
        if (Config.DEBUG)
            Log.d(TAG, "onStop");
        super.onStop();
    }
    public static int getNumber()
    {
        number++;
        return number;
    }
}

<?xml version="1.0" encoding="utf-8"?>
 
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.test.app"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />
    <application android:label="@string/app_name">
        <activity android:name=".PluginTest"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>
Again, take note of the package and android:name properties.
Continuing on, we’re now ready to build and compile our Java program. Create a new file called build.xml and place it in the \Android\ folder. The contents are:
<?xml version="1.0" encoding="UTF-8"?>
 
<project name="CompilePluginTutorialAndroidJava">
    <!-- Change this in order to match your configuration -->
    <property name="sdk.dir" value="C:\android-sdk-windows"/>
    <property name="target" value="android-10"/>
    <property name="unity.androidplayer.jarfile" value="C:\Program Files (x86)\Unity\Editor\Data\PlaybackEngines\androiddevelopmentplayer\bin\classes.jar"/>
    <!-- Source directory -->
    <property name="source.dir" value="." />
    <!-- Output directory for .class files-->
    <property name="output.dir" value="./classes"/>
    <!-- Name of the jar to be created. Please note that the name should match the name of the class and the name
    placed in the AndroidManifest.xml-->
    <property name="output.jarfile" value="PluginTutorial.jar"/>
      <!-- Creates the output directories if they don't exist yet. -->
    <target name="-dirs"  depends="message">
        <echo>Creating output directory: ${output.dir} </echo>
        <mkdir dir="${output.dir}" />
    </target>
   <!-- Compiles this project's .java files into .class files. -->
    <target name="compile" depends="-dirs"
                description="Compiles project's .java files into .class files">
        <javac encoding="ascii" target="1.6" debug="true" destdir="${output.dir}" verbose="${verbose}" includeantruntime="false">
            <src path="${source.dir}" />
            <classpath>
                <pathelement location="${sdk.dir}\platforms\${target}\android.jar"/>
                <pathelement location="${unity.androidplayer.jarfile}"/>
            </classpath>
        </javac>
    </target>
    <target name="build-jar" depends="compile">
        <zip zipfile="${output.jarfile}"
            basedir="${output.dir}" />
    </target>
    <target name="clean-post-jar">
         <echo>Removing post-build-jar-clean</echo>
         <delete dir="${output.dir}"/>
    </target>
    <target name="clean" description="Removes output files created by other targets.">
        <delete dir="${output.dir}" verbose="${verbose}" />
    </target>
    <target name="message">
     <echo>Android Ant Build for Unity Android Plugin</echo>
        <echo>   message:      Displays this message.</echo>
        <echo>   clean:     Removes output files created by other targets.</echo>
        <echo>   compile:   Compiles project's .java files into .class files.</echo>
        <echo>   build-jar: Compiles project's .class files into .jar file.</echo>
    </target>
</project>