Java tutorial
//package com.java2s; /* * JBoss, Home of Professional Open Source. * Copyright 2014 Red Hat, Inc., and individual contributors * as indicated by the @author tags. * * 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.lang.reflect.Array; import java.util.Arrays; import java.util.Collections; import java.util.List; public class Main { static <E> List<E> getList(List<E> orig, Class<E> elemType) { if (orig == null || orig.isEmpty()) { return Collections.emptyList(); } else if (orig.size() == 1) { return Collections.singletonList(orig.get(0)); } else { return Collections.unmodifiableList(Arrays.asList(orig.toArray(createArray(elemType, orig.size())))); } } @SuppressWarnings("unchecked") private static <E> E[] createArray(Class<E> elemType, int length) { return (E[]) Array.newInstance(elemType, length); } }