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java string api

String class:-String is an object which is used to represent a sequence of characters and created by String class which is available in java.lang.String package. String is an immutable class we cannot modify object once created.

Example1:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s="javaindore";
System.out.println(s);
String s1=new String(s);
System.out.println(s1);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
javaindore
javaindore


Example2:- TestString.java

class TestString
{
public static void main(String[]args)
{
String s1="javaindore";
String s2="javaindore";
System.out.println(s1==s2);
String s3="javaindore12";
String s4="javaindore123";
System.out.println(s3==s4);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
true
false
Example3:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1="javaindore";
String s2="javaindore123";
System.out.println(s1==s2);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
false

Example4:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1="javaindore";
String s2="javaindore";
System.out.println(s1.equals(s2));
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
true
Example5:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1="javaindore";
String s2="javaindore";
System.out.println(s1.equals(s2));
System.out.println(s1==s2);
System.out.println(s1.hashCode());
System.out.println(s2.hashCode());
System.out.println(s1.hashCode()==s2.hashCode());
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
true
true
-87548091
-87548091
true
Example6:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
String s2=new String("javaindore");
System.out.println(s1.equals(s2));
System.out.println(s1==s2);
System.out.println(s1.hashCode());
System.out.println(s2.hashCode());
System.out.println(s1.hashCode()==s2.hashCode());
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
true
false
-87548091
-87548091
true
Example7:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
String s2=new String("javaindore123");
System.out.println(s1.equals(s2));
System.out.println(s1==s2);
System.out.println(s1.hashCode());
System.out.println(s2.hashCode());
System.out.println(s1.hashCode()==s2.hashCode());
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
false
false
-87548091
-1099981619
false

Example8:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
System.out.println(s1);
System.out.println(s1.concat("123"));
System.out.println(s1);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
javaindore
javaindore123
javaindore

Example9:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
System.out.println(s1);
s1=s1.concat("123");
System.out.println(s1);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
javaindore
javaindore123
Example10:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
System.out.println(s1);
s1="HelloIndore";
System.out.println(s1);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
javaindore
HelloIndore
Example11:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
String s2=new String("javaindore");
System.out.println(s1==s2);
s1="HelloIndore";
s2="HelloIndore";
System.out.println(s1==s2);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
false
true
Example12:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
StringBuffer s2=new StringBuffer("javaindore");
System.out.println(s1.equals(s2));
StringBuilder s3=new StringBuilder("javaindore");
System.out.println(s1.equals(s3));
System.out.println(s1.concat("106"));
System.out.println(s2.append("106"));
System.out.println(s3.append("106"));
System.out.println(s1);
System.out.println(s2);
System.out.println(s3);
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
false
false
javaindore106
javaindore106
javaindore106
javaindore
javaindore106
javaindore106
Example13:- TestString.java
class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
System.out.println(s1.toUpperCase());
System.out.println(s1.toLowerCase());
s1="     India    ";
System.out.println(s1);
System.out.println(s1.trim());
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
JAVAINDORE
javaindore
     India

India
Example14:- TestString.java

class TestString
{
public static void main(String[]args)
{
System.out.println("String class equals method Demo");
String s1=new String("javaindore");
String s2=new String("javaindore");
System.out.println(s1.equals(s2));
System.out.println("StringBuffer class equals method Demo");
StringBuffer s3=new StringBuffer("javaindore");
StringBuffer s4=new StringBuffer("javaindore");
System.out.println(s3.equals(s4));
System.out.println("StringBuilder class equals method Demo");
StringBuilder s5=new StringBuilder("javaindore");
StringBuilder s6=new StringBuilder("javaindore");
System.out.println(s5.equals(s6));
}
}

Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
String class equals method Demo
true
StringBuffer class equals method Demo
false
StringBuilder class equals method Demo
false

Example15:-TestString.java(string to array)

class TestString
{
public static void main(String[]args)
{
String s="javaindore";
char c[]=s.toCharArray();
for(int i=0;i<c.length;i++)
{
System.out.print(c[i]);
}
}
}

Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
Javaindore

Example16:-TestString.java(toString()  method)

class TestString
{
public static void main(String[]args)
{
String s1=new String("javaindore");
System.out.println(s1);
StringBuffer s2=new StringBuffer("javaindore");
System.out.println(s2);
StringBuilder s3=new StringBuilder("javaindore");
System.out.println(s3);
}
}

Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
javaindore
javaindore
javaindore

Example17:- TestString.java(compareTo() method)

class TestString
{
public static void main(String[]args)
{
String s1=new String("java");
String s2=new String("indore");
String s3="java";
System.out.println(s1.compareTo(s2));
System.out.println(s2.compareTo(s1));
System.out.println(s1.compareTo(s3));
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
1
-1
0

Example18:- TestString.java(primitive to String)

class TestString
{
public static void main(String[]args)
{
String s=null;
System.out.println("boolean to String "+s.valueOf(true));
System.out.println("int to String "+s.valueOf(29));
System.out.println("double to String "+s.valueOf(29.29));
System.out.println("float to String "+s.valueOf(29.29f));
System.out.println("long to String "+s.valueOf(29L));
byte b=29;
System.out.println("byte to String "+s.valueOf(b));
short s1=29;
System.out.println("short to String "+s.valueOf(s1));
char c='A';
System.out.println("char to String "+s.valueOf(c));
}
}
Output:-
C:\JAVATECH>javac TestString.java
C:\JAVATECH>java TestString
boolean to String true
int to String 29
double to String 29.29
float to String 29.29
long to String 29
byte to String 29
short to String 29

char to String A
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