lambda expressions can be applied on interfaces with singlemethod only in java code example

Example 1: how to use lambda in java

StateOwner stateOwner = new StateOwner();

stateOwner.addStateListener(
    (oldState, newState) -> System.out.println("State changed")
);

Example 2: lambda java advanced condition

public void method() {    String localVariable = "Local";    Foo foo = parameter -> {        String localVariable = parameter;        return localVariable;    };}