61 lines
2.0 KiB
Java
61 lines
2.0 KiB
Java
/*
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* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import java.io.*;
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import java.nio.*;
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import java.nio.channels.*;
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public class CheckClassFileVersion {
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static String get(String fn) throws IOException {
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ByteBuffer bb = ByteBuffer.allocate(1024);
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FileChannel fc = new FileInputStream(fn).getChannel();
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try {
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bb.clear();
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if (fc.read(bb) < 0)
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throw new IOException("Could not read any bytes");
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bb.flip();
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int minor = bb.getShort(4);
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int major = bb.getShort(6);
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return major + "." + minor;
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} finally {
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fc.close();
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}
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}
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public static void main(String[] args) throws IOException {
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String cfv = get(args[0]);
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if (args.length == 1) {
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System.out.println(cfv);
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return;
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}
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if (!cfv.equals(args[1])) {
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System.err.println("Class-file version mismatch: Expected "
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+ args[1] + ", got " + cfv);
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System.exit(1);
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}
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}
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}
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