Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.List; import java.util.function.Predicate; public class Main { public static <T> int positionOf(List<T> list, Predicate<T> predicate) { int i = 0; for (T item : list) { if (predicate.test(item)) { return i; } i++; } return -1; } public static <T> int positionOf(List<T> list, T item) { return positionOf(list, (Predicate<T>) x -> x.equals(item)); } }