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package java.lang;

A resource that must be closed when it is no longer needed.
Author:Josh Bloch
Since:1.7
/** * A resource that must be closed when it is no longer needed. * * @author Josh Bloch * @since 1.7 */
public interface AutoCloseable {
Closes this resource, relinquishing any underlying resources. This method is invoked automatically on objects managed by the try-with-resources statement.

While this interface method is declared to throw Exception, implementers are strongly encouraged to declare concrete implementations of the close method to throw more specific exceptions, or to throw no exception at all if the close operation cannot fail.

Implementers of this interface are also strongly advised to not have the close method throw InterruptedException. This exception interacts with a thread's interrupted status, and runtime misbehavior is likely to occur if an InterruptedException is suppressed. More generally, if it would cause problems for an exception to be suppressed, the AutoCloseable.close method should not throw it.

Note that unlike the close method of Closeable, this close method is not required to be idempotent. In other words, calling this close method more than once may have some visible side effect, unlike Closeable.close which is required to have no effect if called more than once. However, implementers of this interface are strongly encouraged to make their close methods idempotent.

Throws:
  • Exception – if this resource cannot be closed
/** * Closes this resource, relinquishing any underlying resources. * This method is invoked automatically on objects managed by the * {@code try}-with-resources statement. * * <p>While this interface method is declared to throw {@code * Exception}, implementers are <em>strongly</em> encouraged to * declare concrete implementations of the {@code close} method to * throw more specific exceptions, or to throw no exception at all * if the close operation cannot fail. * * <p><em>Implementers of this interface are also strongly advised * to not have the {@code close} method throw {@link * InterruptedException}.</em> * * This exception interacts with a thread's interrupted status, * and runtime misbehavior is likely to occur if an {@code * InterruptedException} is {@linkplain Throwable#addSuppressed * suppressed}. * * More generally, if it would cause problems for an * exception to be suppressed, the {@code AutoCloseable.close} * method should not throw it. * * <p>Note that unlike the {@link java.io.Closeable#close close} * method of {@link java.io.Closeable}, this {@code close} method * is <em>not</em> required to be idempotent. In other words, * calling this {@code close} method more than once may have some * visible side effect, unlike {@code Closeable.close} which is * required to have no effect if called more than once. * * However, implementers of this interface are strongly encouraged * to make their {@code close} methods idempotent. * * @throws Exception if this resource cannot be closed */
void close() throws Exception; }