Samsung S6102 Galaxy Y Duos

public class MainActivity extends Activity {
TextView txtV;
	Context cntx;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        txtV = (TextView)findViewById(R.id.idLabel);
        cntx = this;
        StringBuilder strBuild = new StringBuilder();
        
         GregorianCalendar cal = new GregorianCalendar();
         Boolean b = cal.isLeapYear(2012); // true
         strBuild.append("Is leap year 2012? " + b + "

");
         b = cal.isLeapYear(2014);         // false
         strBuild.append("Is leap year 2014? " + b + "

");
         
         
         txtV.setText(strBuild);
    }
}

// in AndroidManifest.xml
<Activity
 android:screenOrientation="portrait" // or landscape

// in MyActivity.java
boolean mbOrientacionLandscape = false;
int nOrientation =	getResources().getConfiguration().orientation;
if(mbOrientacionLandscape==true){
	 getResources().getConfiguration();
	if(nOrientation != Configuration.ORIENTATION_LANDSCAPE)
	setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
	
}
else{
	if(nOrientation != Configuration.ORIENTATION_PORTRAIT)
	setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

// file name MyFirstClass.java

import java.util.*;
import java.lang.Math;
import java.io.*;
import javax.swing.*;

public class MyFirstClass{ // start of program
  public static void main(String[] args) { // basic  function main

// variables and calculation
int a=2;
int b=3;
int c=Integer.parseInt(JOptionPane.showInputDialog(" Put number: ", "1"));
System.out.println("Number is: "+c);
System.out.println(a+" * "+b+" = "+(a*b));
System.out.println("a^3 "+Math.pow(a,b));

//array
int[] array_my=new int[10];
array_my[0]=3;
array_my[1]=5;
System.out.println("Number of elements "+array_my.length+" 1 + 2 element of array "+(array_my[0]+array_my[1]));

//strings
String txt="Quick red fox";
String txt2=JOptionPane.showInputDialog("Write text: ", "word");
System.out.println("Text is: "+txt2);
String[] count_of_word=txt.split(" ");
System.out.println("Length: "+txt.length()+" Count of words "+count_of_word.length);
System.out.println(txt +" -> "+txt.replace("red","brown"));
System.out.println("First 5 chars of string is: "+ txt.substring(0,5));

//for a if
for(int i=0; i<10;i++){
	if(i==3)System.out.println("i equal "+i);
	}

// file
try {
  File soubor=new File("some_file.txt");
  if(!soubor.exists()){
	System.out.println("File dont exist");
  }
  else { // utf-8 encoding
    BufferedReader in1 = new BufferedReader(new InputStreamReader(new FileInputStream(soubor),"UTF-8"));
    BufferedWriter out1 = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("zapis.txt"),"UTF-8"));
    String str;
      while ((str = in1.readLine())!=null){
        System.out.println(str);
        out1.write(str+"

");
      }
    in1.close();
    out1.close();
   }
 } catch(IOException e){System.out.println("Error " + e);}

// dir
 File pathName = new File("some_dir");
 String[] fileNames = pathName.list();
 if(pathName.exists())
 System.out.println("Name of first file in  \"some_dir\": "+fileNames[0]);
 else System.out.println("dir not exist");

//function
int nResult = calculateMyFc(3,5);
System.out.println("Result of function: "+nResult);

} // end of function main

// new function , you can add to end MyFc = my function
public static int calculateMyFc(int a, int b){
return (a+b);
}

} // end of class of program

public class Main extends Activity {
	    private SensorManager mSensorManager;
	    private PowerManager mPowerManager;
	    private WindowManager mWindowManager;
	    private WakeLock mWakeLock;
	    private Button button;
	    private TextView textView;

	    /** Called when the activity is first created. */
	    @Override
	    public void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);
try{
	        // Get an instance of the SensorManager
	        mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);

	        // Get an instance of the PowerManager
	        mPowerManager = (PowerManager) getSystemService(POWER_SERVICE);

	        // Get an instance of the WindowManager
	        mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
	        mWindowManager.getDefaultDisplay();

	        // Create a bright wake lock
	        mWakeLock = mPowerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, getClass()
	                .getName());

	        setContentView(R.layout.main);
	        textView = (TextView)findViewById(R.id.textView1);
	        button = (Button)findViewById(R.id.button1);
	        button.setOnClickListener(mButtonStopListener);
	       
	        
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			Log.e("onCreate", e.getMessage());
		}
} // END onCreate
	    
	    View.OnClickListener mButtonStopListener = new OnClickListener() {
	    	public void onClick(View v) {
		        try {
					mWakeLock.release();
					textView.setText("mWakeLock.release()");
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
					Log.e("onPause",e.getMessage());
				}
	    	
	    	}
	    };

	    @Override
	    protected void onResume() {
	        super.onResume();
	        /*
	         * when the activity is resumed, we acquire a wake-lock so that the
	         * screen stays on, since the user will likely not be fiddling with the
	         * screen or buttons.
	         */
	        
	        try {
				mWakeLock.acquire();
				textView.setText("mWakeLock.acquire()");
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				Log.e("onResume", e.getMessage());
			}

	    }

	    @Override
	    protected void onPause() {
	        super.onPause();

	        // and release our wake-lock
	        try {
				mWakeLock.release();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				Log.e("onPause",e.getMessage());
			}
	    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="//schemas.android.com/apk/res/android"
      package="cz.okhelp.Main"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="7" />
    <uses-permission android:name="android.permission.HARDWARE_TEST"></uses-permission>
<uses-permission android:name="android.permission.VIBRATE"></uses-permission>

<uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ScreenBrightnessActivity"
                  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>