[java] How do I convert strings between uppercase and lowercase in Java?

What is the method for converting strings in Java between upper and lower case?

String#toLowerCase

There are methods in the String class; toUppercase() and toLowerCase().

i.e.

String input = "Cricket!";
String upper = input.toUpperCase(); //stores "CRICKET!"
String lower = input.toLowerCase(); //stores "cricket!" 

This will clarify your doubt

Yes. There are methods on the String itself for this.

Note that the result depends on the Locale the JVM is using. Beware, locales is an art in itself.

Coverting the first letter of word capital

input:

hello world

String A = hello;
String B = world;
System.out.println(A.toUpperCase().charAt(0)+A.substring(1) + " " + B.toUpperCase().charAt(0)+B.substring(1));

Output:

Hello World

Assuming that all characters are alphabetic, you can do this:

From lowercase to uppercase:

// Uppercase letters. 
class UpperCase {  
  public static void main(String args[]) { 
    char ch;
    for(int i=0; i < 10; i++) { 
      ch = (char) ('a' + i);
      System.out.print(ch); 

      // This statement turns off the 6th bit.   
      ch = (char) ((int) ch & 65503); // ch is now uppercase
      System.out.print(ch + " ");  
    } 
  } 
}

From uppercase to lowercase:

// Lowercase letters. 
class LowerCase {  
  public static void main(String args[]) { 
    char ch;
    for(int i=0; i < 10; i++) { 
      ch = (char) ('A' + i);
      System.out.print(ch);
      ch = (char) ((int) ch | 32); // ch is now uppercase
      System.out.print(ch + " ");  
    } 
  } 
}