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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 */

/*
 * @test TestLogTruncation
 * @summary Ensure log files are truncated and not appended on VM startup
 * @library /testlibrary
 */

import java.nio.file.Files;
import java.nio.file.Paths;

import jdk.test.lib.ProcessTools;
import jdk.test.lib.OutputAnalyzer;

import static jdk.test.lib.Asserts.assertEquals;

public class TestLogTruncation {

    public static void main(String[] args) throws Exception {
        // Run two VMs with the same log file
        for (int i = 0; i < 2; i++) {
            ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-Xlog:logging=trace:out.log", "-version");
            OutputAnalyzer output = new OutputAnalyzer(pb.start());
            output.shouldHaveExitValue(0);
        }

        // Message should only appear once in the log file, since the second run should overwrite the previous log
        long occurences = Files.lines(Paths.get("out.log"))
                .filter(s -> s.contains("Log configuration fully initialized.")).count();
        assertEquals(occurences, 1L, "Log file not truncated on VM startup");
    }
}