adb kill-server
adb start-server
import android.app.Activity;
import android.os.Bundle;
public class HelloAndroid extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloAndroid extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv = new TextView(this);
tv.setText("Hello, Android");
setContentView(tv);
}
}
^<Path> (^ is for line start). Don't forget to check "Bookmark lines" and Press "Mark All" 
^<Path> (^ is for line start). Don't forget to check "Bookmark lines" and Press "Mark All" 
package com.JavaPages4All.md5encryption;
import java.security.MessageDigest;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Md5 extends Activity
{
EditText textview;
Button get;
TextView textlbl;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.md5);
textview=(EditText)findViewById(R.id.textview);
get=(Button)findViewById(R.id.get);
textlbl=(TextView)findViewById(R.id.textlbl);
get.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View arg0)
{
String strpassword=textview.getText().toString();
if(strpassword!=null && strpassword.trim().length()!=0)
{
String md5=getMD5Encryption(strpassword);
textlbl.setText(md5);
}
}
});
}
public String getMD5Encryption(String strpassword)
{
try
{
// Create MD5 Hash
MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
digest.update(strpassword.getBytes());
byte messageDigest[] = digest.digest();
// Create Hex String
StringBuffer hexString = new StringBuffer();
for (int i = 0; i < messageDigest.length; i++)
{
String h = Integer.toHexString(0xFF & messageDigest[i]);
while (h.length() < 2)
h = "0" + h;
hexString.append(h);
}
return hexString.toString();
} catch (Exception e)
{
e.printStackTrace();
}
return "";
}
}
|
|
package raja.JavaPages4All;
import java.util.Date;
/**
* @author Raja(JavaPages4All)
*/
public class TestPojo
{
private String blogName;
private Date date;
public TestPojo(String blogName,Date date)
{
this.blogName=blogName;
this.date = date;
}
public String getBlogName()
{
return this.blogName;
}
public Date getDate()
{
return this.date;
}
}
|
package raja.JavaPages4All;
import java.util.Date;
public class ImmutableTest
{
/**
* @author Raja(JavaPages4All)
*/
public static void main(String[] args)
{
/*
* String Class is Immutable.
* Date Class is Mutable.
*/
String str="JavaPages4All";
Date myDate = new Date();
TestPojo pojo =new TestPojo(str,myDate);
/**
* Getting Values from TestPojo Reference Object(When First Time)
*/
System.out.println(pojo.getBlogName());
System.out.println( pojo.getDate() );
/**
* String str Object value changing so it is Creating Newly(Immutable).
* Date myDate Object value changing so it is Updated the
* Previous Object myDate Value(Mutable)
*/
str="Raja";
myDate.setMonth( myDate.getMonth() + 1 );
/**
* Getting Values from TestPojo Reference Object
* (When Second Time object Values Changed)
*/
System.out.println(pojo.getBlogName()+" "+str);
System.out.println( pojo.getDate() );
}
}
|
package raja.JavaPages4all;
import java.awt.Point;
public class Immutability
{
/**
* @author Raja(JavaPages4All)
* @param args
*/
public static void main(String[] args)
{
Point pt= new Point( 0, 0 );
System.out.println( pt);
pt.setLocation( 1.0, 0.0 );
System.out.println( pt);
String str= new String( "old String" );
System.out.println( str);
str.replaceAll( "old", "new" );
System.out.println( str);
}
}
|
java.awt.Point[0.0, 0.0] java.awt.Point[1.0, 0.0] old String old String
We are only looking at a single instance of each object, but we can see that the contents of pt has changed, but the contents of str did not. To show what happens when we try to change the value of str, we'll extend the previous example.
package raja.JavaPages4all;
import java.awt.Point;
public class Immutability
{
/**
* @author Raja(JavaPages4All)
* @param args
*/
public static void main(String[] args)
{
Point pt= new Point( 0, 0 );
System.out.println( pt);
pt.setLocation( 1.0, 0.0 );
System.out.println( pt);
String str= new String( "old String" );
System.out.println( str );
str= new String( "new String" );
System.out.println( str );
}
}
|
old String new StringNow we find that the value displayed by the str variable has changed. We have defined immutable objects as being unable to change in value, so what is happening? Let's extend the example again to watch the str variable closer.
package raja.JavaPages4all;
public class Immutability
{
/**
* @author Raja(JavaPages4All)
* @param args
*/
public static void main(String[] args)
{
//Comparison
String str = new String( "old String" );
String myCache = str ;
System.out.println( "String Comparison: " + str.equals( myCache ) );
System.out.println( "Object Comparison: " + ( str == myCache ) );
str = "not " + str ;
System.out.println( "String Comparison: " + str.equals( myCache ) );
System.out.println( "Object Comparison: " + ( str == myCache ) );
}
}
|
String Comparison: true Object Comparison: true String Comparison: false Object Comparison: falseWhat this shows is that variable str is referencing a new instance of the String class. The contents of the object didn't change; we discarded the instance and changed our reference to a new one with new contents.