SupplierExamples.java

import java.util.Optional;
import java.util.function.Supplier;

public class SuppliersExamples {

    @Test
    public void lazyValuation() throws Exception {

        Optional<Integer> ok = executeDangerousAction(() -> 4 / 2);
        Optional<Integer> divisionByZero = executeDangerousAction(() -> 4 / 0);

        assertThat(ok).isPresent().hasValue(2);
        assertThat(divisionByZero).isEmpty();
    }

    private <A> Optional<A> executeDangerousAction(Supplier<A> action){
        A value = null;
        try {
            value = action.get();
        } catch (Exception e) {
        }
        return Optional.ofNullable(value);
    }

  
}