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      1 /*
      2  * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
      3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      4  *
      5  * This code is free software; you can redistribute it and/or modify it
      6  * under the terms of the GNU General Public License version 2 only, as
      7  * published by the Free Software Foundation.  Oracle designates this
      8  * particular file as subject to the "Classpath" exception as provided
      9  * by Oracle in the LICENSE file that accompanied this code.
     10  *
     11  * This code is distributed in the hope that it will be useful, but WITHOUT
     12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     14  * version 2 for more details (a copy is included in the LICENSE file that
     15  * accompanied this code).
     16  *
     17  * You should have received a copy of the GNU General Public License version
     18  * 2 along with this work; if not, write to the Free Software Foundation,
     19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     20  *
     21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     22  * or visit www.oracle.com if you need additional information or have any
     23  * questions.
     24  */
     25 
     26 package java.lang;
     27 
     28 /**
     29  * A resource that must be closed when it is no longer needed.
     30  *
     31  * @author Josh Bloch
     32  * @since 1.7
     33  */
     34 public interface AutoCloseable {
     35     /**
     36      * Closes this resource, relinquishing any underlying resources.
     37      * This method is invoked automatically on objects managed by the
     38      * {@code try}-with-resources statement.
     39      *
     40      * <p>While this interface method is declared to throw {@code
     41      * Exception}, implementers are <em>strongly</em> encouraged to
     42      * declare concrete implementations of the {@code close} method to
     43      * throw more specific exceptions, or to throw no exception at all
     44      * if the close operation cannot fail.
     45      *
     46      * <p><em>Implementers of this interface are also strongly advised
     47      * to not have the {@code close} method throw {@link
     48      * InterruptedException}.</em>
     49      *
     50      * This exception interacts with a thread's interrupted status,
     51      * and runtime misbehavior is likely to occur if an {@code
     52      * InterruptedException} is {@linkplain Throwable#addSuppressed
     53      * suppressed}.
     54      *
     55      * More generally, if it would cause problems for an
     56      * exception to be suppressed, the {@code AutoCloseable.close}
     57      * method should not throw it.
     58      *
     59      * <p>Note that unlike the {@link java.io.Closeable#close close}
     60      * method of {@link java.io.Closeable}, this {@code close} method
     61      * is <em>not</em> required to be idempotent.  In other words,
     62      * calling this {@code close} method more than once may have some
     63      * visible side effect, unlike {@code Closeable.close} which is
     64      * required to have no effect if called more than once.
     65      *
     66      * However, implementers of this interface are strongly encouraged
     67      * to make their {@code close} methods idempotent.
     68      *
     69      * @throws Exception if this resource cannot be closed
     70      */
     71     void close() throws Exception;
     72 }
     73