Here you can find the source of toDouble(Object number)
public static double toDouble(Object number)
//package com.java2s; /*/*ww w . j a v a 2 s. com*/ * Copyright 2014 Luis Abdul Ch?vez Bustamante. * * 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. */ public class Main { public static double toDouble(Object number) { double value = 0f; if (number instanceof Number) { if (number instanceof Long) { value += (long) number; } if (number instanceof Integer) { value += (int) number; } if (number instanceof Float) { value += (float) number; } } return value; } }