SysProp.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the Classpath exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * 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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package com.sun.btrace.samples;

import com.sun.btrace.annotations.*;
import static com.sun.btrace.BTraceUtils.*;

/**
 * This BTrace script demonstrates that it is okay
 * to trace bootstrap classes and call the same 
 * inside the trace actions. In this example, we insert
 * a probe into System.getProperty() method and call 
 * System.getProperty [through property() built-in function]
 * without getting into infinite recursion. A thread local 
 * flag is used by BTrace to avoid infinite recursion here.
 */
@BTrace public class SysProp {
    @OnMethod(
        clazz="java.lang.System",
        method="getProperty"
    )
    public static void onGetProperty(String name) {
        println(name);
        // call property safely here.
        println(Sys.Env.property(name));
    } 
}