Here you can find the source of mean(Collection extends Number> terms)
public static float mean(Collection<? extends Number> terms)
//package com.java2s; /**//from w w w . j a v a2s .com * Copyright 2009 Kevin J. Menard Jr. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.util.*; public class Main { public static float mean(Collection<? extends Number> terms) { if (terms.isEmpty()) { return 0; } float total = 0; for (Number term : terms) { total += term.doubleValue(); } return ((float) total) / terms.size(); } }