The difference is visible when you use the single quote with the + sign. The char value is converted to the ascii value and then summed up.

However, you have to be careful when using in concatenation with a String. The value is just concatenated and not ascii converted.

public class UsageOfSingleQuote{   public static void main(String args[])   {      UsageOfSingleQuote usageOfSingleQuote = new UsageOfSingleQuote();      usageOfSingleQuote.proceed();   }      private void proceed()   {      System.out.println("Prints: " + 'A'); //Prints the char      System.out.println("Prints: " + 'a'); //Prints the char      System.out.println('A' + 'A'); //Converts to ascii value , sums up and then prints the value      System.out.println("Abc" + 'A'); //Pure String concatenation   }}/*

Expected output:

[root@mypc]# java UsageOfSingleQuotePrints: APrints: a130AbcA*/