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使用Open JDK 10.0.2时,VirtualMachine attach抛出com.sun.tools.attach.AgentLoadException:0

java-attach-api javaagents java

0

Ramesh Subramanian · 技术社区 · 5 年前

com.sun.tools.attach.VirtualMachine Java API。我的目标应用程序(Tomcat)正在使用Oracle Hot Spot 1.7.0_80版运行。我正试图通过另一个使用Open JDK 10.0.2的Java程序(在同一台机器上)的动态连接来连接tomcat。我正在使用下面的代码

...............
String agentPath = Agent.class.getProtectionDomain().getCodeSource().getLocation().getPath();
agentPath = convertFileSeparators(agentPath, File.separatorChar);
String agentInstallDir = agentPath.substring(0, agentPath.lastIndexOf(File.separator));
System.out.println("My Java agent installed on the location :"+agentPath);
StringBuilder sb = new StringBuilder();
sb.append("MY_RELIC_HOME").append("=").append(agentInstallDir);
if (agentArgs != null) {
     sb.append(",").append(agentArgs);
}
com.sun.tools.attach.VirtualMachine virtualMachine =  com.sun.tools.attach.VirtualMachine.attach(vmID);
virtualMachine.loadAgent(agentPath, sb.toString());
.........

我可以成功地附加到目标应用程序,但在附加后,在附加程序(运行open JDK 10.0.2)中遇到以下异常。

com.sun.tools.attach.AgentLoadException: 0
    at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.loadAgentLibrary(HotSpotVirtualMachine.java:104)
    at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.loadAgentLibrary(HotSpotVirtualMachine.java:115)
    at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.loadAgent(HotSpotVirtualMachine.java:139)
    at com.eg.agent.Agent.main(Agent.java:582)

582号线上的代码是 virtualMachine.loadAgent(agentPath, sb.toString());

如果我使用Java 7或8运行attach程序,没有异常,attach就是成功的。

com.sun.tools.attach.AgentLoadException: 0 使用JDK 10时发生异常?

1 回复 | 直到 5 年前

1

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Ramesh Subramanian 5 年前

在查找了 sun.tools.attach.HotSpotVirtualMachine

以下代码来自1.8 这表明 result 为零表示VMAttach成功。

private void loadAgentLibrary(String agentLibrary, boolean isAbsolute, String options)
    throws AgentLoadException, AgentInitializationException, IOException
{
    InputStream in = execute("load",
                             agentLibrary,
                             isAbsolute ? "true" : "false",
                             options);
    try {
        int result = readInt(in);
        if (result != 0) {
            throw new AgentInitializationException("Agent_OnAttach failed", result);
        }
    } finally {
        in.close();

    }
}

下面的代码来自java 10 在VM Attach中,当 结果 "return code: 0" (但是在1.8中 0 ).

private void loadAgentLibrary(String agentLibrary, boolean isAbsolute, String options) 
    throws AgentLoadException, AgentInitializationException, IOException 
{ 
    String msgPrefix = "return code: "; 
    InputStream in = execute("load", 
                             agentLibrary, 
                             isAbsolute ? "true" : "false", 
                             options); 
    try (BufferedReader reader = new BufferedReader(new InputStreamReader(in))) { 
        String result = reader.readLine(); 
        if (result == null) { 
            throw new AgentLoadException("Target VM did not respond"); 
        } else if (result.startsWith(msgPrefix)) { 
            int retCode = Integer.parseInt(result.substring(msgPrefix.length())); 
            if (retCode != 0) { 
                throw new AgentInitializationException("Agent_OnAttach failed", retCode); 
            } 
        } else { 
            throw new AgentLoadException(result); 
        } 
    } 
}

在我的例子中,Java7/8代码(目标应用程序)返回作为 0个 (这意味着VM Attach是成功的)到Java 10代码(VM Attach code),期望结果应该是 “返回代码:0”