Java Class New Instance newInstance(Class klass)

Description

new Instance

License

Apache License

Declaration

@SuppressWarnings("unchecked")
    public static <T> T newInstance(Class<T> klass) 

Method Source Code

//package com.java2s;
/**/*from  w w  w  .  ja v  a  2s .  c  o  m*/
 * 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.
 */

import java.lang.reflect.Constructor;

import java.util.Map;

import java.util.concurrent.ConcurrentHashMap;

public class Main {
    private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE = new ConcurrentHashMap<Class<?>, Constructor<?>>();

    @SuppressWarnings("unchecked")
    public static <T> T newInstance(Class<T> klass) {
        T result;
        try {
            Constructor<T> meth = (Constructor<T>) CONSTRUCTOR_CACHE.get(klass);
            if (meth == null) {
                meth = klass.getDeclaredConstructor(new Class[] {});
                meth.setAccessible(true);
                CONSTRUCTOR_CACHE.put(klass, meth);
            }
            result = meth.newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return result;
    }
}

Related

1. newInstance(Class cls, Object... args)
2. newInstance(Class clz, Class argType, K arg)
3. newInstance(Class componentType, int size)
4. newInstance(Class elementType, int len)
5. newInstance(Class klass)
6. newInstance(Class klass)
7. newInstance(Class klass)
8. newInstance(Class klass, Class[] paramTypes, Object... params)
9. newInstance(Class klass, Object... args)