String Concatenation in Java

In java, string concatenation forms a new string that is the combination of multiple strings. There are two ways to concat string in java: By + (string concatenation) operator By concat() method 1) String Concatenation by + (string concatenation) operator Java string concatenation operator (+) is used to add strings. For Example: class TestStringConcatenation1{    public static void main(String args[]){      String s="Sachin"+" Tendulkar";      System.out.println(s);//Sachin Tendulkar    }   }   Output:Sachin Tendulkar The Java compiler transforms above code to this: String s=(new StringBuilder()).append("Sachin").append(" Tendulkar).toString();   In java, String concatenation is implemented through the StringBuilder (or StringBuffer) class and its append method. String concatenation operator produces a new string by appending the second operand onto the end of the first operand. The string concatenation operator can concat not only string but primitive values also. For Example: class TestStringConcatenation2{    public static void main(String args[]){      String s=50+30+"Sachin"+40+40;      System.out.println(s);//80Sachin4040    }   }   80Sachin4040 Note: After a string literal, all the + will be treated as string concatenation operator. 2) String Concatenation by concat() method The String concat() method concatenates the specified string to the end of current string. Syntax: public String concat(String another)   Let's see the example of String concat() method. class TestStringConcatenation3{    public static void main(String args[]){      String s1="Sachin ";      String s2="Tendulkar";      String s3=s1.concat(s2);      System.out.println(s3);//Sachin Tendulkar     }   }   Sachin Tendulkar