/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * *   - Redistributions of source code must retain the above copyright *     notice, this list of conditions and the following disclaimer. * *   - Redistributions in binary form must reproduce the above copyright *     notice, this list of conditions and the following disclaimer in the *     documentation and/or other materials provided with the distribution. * *   - Neither the name of Sun Microsystems nor the names of its *     contributors may be used to endorse or promote products derived *     from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ import java.lang.reflect.Field;import static java.lang.System.out;enum TraceLevel { OFF, LOW, MEDIUM, HIGH, DEBUG }class MyServer {    private TraceLevel level = TraceLevel.OFF;}public class SetTrace {    public static void main(String... args) {	TraceLevel newLevel = TraceLevel.valueOf(args[0]);	try {	    MyServer svr = new MyServer();	    Class<?> c = svr.getClass();	    Field f = c.getDeclaredField("level");	    f.setAccessible(true);	    TraceLevel oldLevel = (TraceLevel)f.get(svr);	    out.format("Original trace level:  %s%n", oldLevel);	    if (oldLevel != newLevel) { 		f.set(svr, newLevel);		out.format("    New  trace level:  %s%n", f.get(svr));	    }        // production code should handle these exceptions more gracefully	} catch (IllegalArgumentException x) {	    x.printStackTrace();	} catch (IllegalAccessException x) {	    x.printStackTrace();	} catch (NoSuchFieldException x) {	    x.printStackTrace();	}    }}