how to make optional paramaters in java code example

Example 1: java how to make a parameter optional

void foo(String a, Integer b) {
    //...
}

void foo(String a) {
    foo(a, 0); // here, 0 is a default value for b
}

foo("a", 2);
foo("a");

Example 2: java how to make a parameter optional

void foo(String a, Optional<Integer> bOpt) {
    Integer b = bOpt.isPresent() ? bOpt.get() : 0;
    //...
}

foo("a", Optional.of(2));
foo("a", Optional.<Integer>absent());