To indicate a long (64-bit) literal, append the suffix L to the literal expression. : long « Java Source And Data Type « SCJP

1. SCJP
2. Java Source And Data Type
3. long

//By default, an integral literal is a 32-bit value. 
public class MainClass {
  public static void main(String[] argv) {
    long aLongValue = 100L;
    aLongValue = 100l; // lower case is legal but hard to read

    System.out.println(aLongValue);
  }
}