Here you can find the source of toCamelCase(final String identifier, boolean capital)
public static String toCamelCase(final String identifier, boolean capital)
//package com.java2s; /*// w w w .j av a 2 s.c om * The MIT License (MIT) * * Copyright (c) 2014 Aaron Cake * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ public class Main { private static final StringBuilder STRING_BUILDER_INSTANCE = new StringBuilder(); public static String toCamelCase(final String identifier, boolean capital) { if (identifier == null) return null; StringBuilder sb = new StringBuilder(identifier); if (sb.length() == 0) return ""; int i = 0; while (i < sb.length()) { if (sb.charAt(i) == '_') { sb.delete(i, i + 1); if (sb.length() > i) { sb.setCharAt(i, Character.toUpperCase(sb.charAt(i))); } } else { sb.setCharAt(i, Character.toLowerCase(sb.charAt(i))); } ++i; } if (capital && sb.length() > 0) { sb.setCharAt(0, Character.toUpperCase(sb.charAt(0))); } return sb.toString(); } /** * Concatenates a list of strings or objects to a single string. * WARNING: NOT THREAD SAFE * @param strings * @return the concatenated string */ public static String toString(final Object... strings) { STRING_BUILDER_INSTANCE.setLength(0); for (final Object o : strings) { STRING_BUILDER_INSTANCE.append(String.valueOf(o)); } return STRING_BUILDER_INSTANCE.toString(); } }