String Constructors Java

In Java, a String object can be created a number of ways. The most frequently used styles are shown here using 9 types of String constructors (including StringBuffer and StringBuilder) defined java.lang.String API.

The 9 constructors are

1. public java.lang.String();
2. public java.lang.String(java.lang.String);
3. public java.lang.String(char[]);
4. public java.lang.String(char[], int startIndex, int numChars);
5. public java.lang.String(int[], int, int);
6. public java.lang.String(byte[]);
7. public java.lang.String(byte[], int startIndex, int numInts);
8. public java.lang.String(java.lang.StringBuffer);
9. public java.lang.String(java.lang.StringBuilder);

The following is the example code using the above 9 string constructors

public class Demo
{
  public static void main(String args[])
  {
    String str1 = new String();                       // using 1st default constructor
    System.out.println("1st constructor: " + str1);   // does not print any value

    String str2 = new String("Second constructor");   // using 2nd constructor
    System.out.println("2nd constructor: " + str2);   // prints Second constructor     

    char charArray1[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'};
    String str3 = new String(charArray1);             // using 3rd constructor
    System.out.println("3rd constructor: " + str3);   // prints abcdefgh    
   
    String str4 = new String(charArray1, 1, 6);       // using 4th constructor
    System.out.println("4th constructor: " + str4);   // prints  bcdefg, from 1 onwards 6 characters

    int intArray1[]={65, 66, 67, 68, 69, 70, 71, 72}; // ASCII numbers are converted to characters implicitly
    String str5 = new String(intArray1, 1, 6);        // using 5th constructor
    System.out.println("5th constructor: " + str5);   // prints BCDEFG   

    byte bytetArray1[] = {65, 66, 67, 68, 69, 70, 71, 72}; // ASCII numbers are converted to characters implicitly
    String str6 = new String(bytetArray1);            // using 6th constructor
    System.out.println("6th constructor: " + str6);   // prints ABCDEFGH
   
    String str7 = new String(bytetArray1, 1, 6);      // using 7th constructor
    System.out.println("7th constructor: " + str7);   // prints BCDEFG   

    StringBuffer sb1 = new StringBuffer("Jyostna");
    String str8 = new String(sb1);		      // using 8th constructor
    System.out.println("8th constructor: " + str8);   // prints Jyostna    

    StringBuilder sb2 = new StringBuilder("Jyothi");
    String str9 = new String(sb2);		      // using 9th constructor
    System.out.println("9th constructor: " + str9);   // prints Jyothi
 }
}

Output screen on String Constructors Java

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