The bitwise operator | provides OR operations : Bitwise Operators « Operators « SCJP

//For OR operations, 0 OR 0 produces 0. Any other combination produces 1.
//In the OR operation, you get a 1 result if either the first operand or the second operand (or both) is 1. 

public class MainClass {
  public static void main(String[] argv) {
    int i = 2;
    int b = 4;

    System.out.println(i | 4);

2.3.Bitwise Operators
2.3.1.Bitwise Operator Summary
2.3.2.Shift Operator Summary
2.3.3.The Bitwise Inversion Operator ~ performs bitwise inversion on integral types.
2.3.4.The Boolean Complement Operator ! inverts the value of a boolean expression.
2.3.5.The bitwise operator & provides bitwise AND
2.3.6.The bitwise operator ^ provides eXclusive-OR (XOR)
2.3.7.The bitwise operator | provides OR operations
2.3.8.Here is an example of the use of the & operator:
2.3.9.Java method to perform various bitwise operations on two integers and display the results