Important Constructors of StringBuffer Class

• StringBuffer() : StringBuffer() generates a blank String buffer with a 16-character initial capacity.

StringBuffer s = new StringBuffer();



• StringBuffer(String str) : Creates a String buffer with the specified string by calling StringBuffer(String String_variable_name).

StringBuffer s = new StringBuffer(10);



• StringBuffer(int capacity) : StringBuffer(int capacity) creates an empty String buffer with the capacity specified as its length.








StringBuffer s = new StringBuffer("DockerTpoint");

Important methods of StringBuffer class

Java String append() Methods

The append() method of the StringBuffer class concatenates the given argument with this string.

 // Java example of String length() Methods

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer("Exam");
      sb.append("Deva"); //  original string is changed
      System.out.println(sb);
  } 
}

DockerTpoint 

Java String insert() Method

The insert() method of the StringBuffer class inserts the given string at the given position with this string.

 // Java example of String insert() Method 

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer("Exam");
      sb.insert(4,"Deva"); //  original string is now changed
      System.out.println(sb);
  } 
}

DockerTpoint 

Java String delete() Method

The delete() method of the StringBuffer class remove the specified string from the begin Index and end Index-1.

 // Java example of String delete  Method 

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer("DockerTpoint"); 
      sb.delete(0,4);  //   original string is now changed
      System.out.println(sb);
  } 
}

mDeva 

Java String replace Method

The substring method of the StringBuffer class replaces the given string between begin Index and end Index-1.

 // Java example of String substring (int start, int end)  Method 

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer("E  Deva"); 
       sb.replace(1,3,"xam");  // it will replace white space, original string is now changed
      System.out.println(sb);
  } 
}

DockerTpoint  

Java String reverse Method

The reverse method of the StringBuffer class reverses the current string.

 // Java example of String concat Method 

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer("DockerTpoint"); 
      sb.reverse();
      System.out.println(sb);
  } 
}

aveDmaxE  

Java String capacity Method

The capacity method of the StringBuffer class returns the buffer's current capacity. The buffer's default capacity is sixteen. If the number of characters exceeds the current capacity, the capacity is increased by (oldcapacity*2)+2.

 // Java example of String indexOf Method 

public class Main {	
    public static void main(String args[]){  		 
      StringBuffer sb = new StringBuffer();
      System.out.println(sb.capacity()); // default value  16
      sb.append("DockerTpoint");
      System.out.println(sb.capacity()); // capicity is 16
      sb.append("I Love India");
      System.out.println(sb.capacity()); // Now (16*2)+2=34     i.e (oldcapacity*2)+2  
  } 
}

16 

16 

34 

Important methods of StringBuffer class

Important methods of StringBuffer class are mention below

Some Interesting StringBuffer Class Facts

• java.lang.StringBuffer extends (or derives from) the Object class.
• Serializable, Appendable, and CharSequence are all StringBuffer class interfaces that have been implemented.
• public final class StringBuffer extends Serializable, CharSequence, and Appendable are all implemented by the object.
• Multiple threads can use string buffers safely. The methods can be synchronized wherever necessary so that all operations on any given instance behave as if they were performed in some sequential order.
• This class synchronizes only on the string buffer performing the operation, not on the source, whenever an operation involving a source sequence occurs (such as appending or inserting from a source sequence).
• StringBuffer inherits some Object class methods such as clone(), equals(), finalize(), getClass(), hashCode(), notifies(), and notifyAll ().
• StringBuilder, J2SE 5 extends Java's already robust string handling capabilities with a new string class. StringBuilder is the name of this new class. It is identical to StringBuffer with one notable exception: it is not synchronized, which means it is not thread-safe. StringBuilder has the advantage of being faster. However, if you are using multithreading, you must use StringBuffer instead of StringBuilder.