Here you can find the source of toDouble(Object literal)
private static Double toDouble(Object literal)
//package com.java2s; /*/*from w w w . ja v a 2s. com*/ * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to you 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 { private static Double toDouble(Object literal) { if (literal instanceof Number) { return ((Number) literal).doubleValue(); } if (literal instanceof String) { try { return Double.valueOf((String) literal); } catch (NumberFormatException e) { // ignore } } return null; } }