48 基于 jdk9 编译的 jdk8 的字节码报错

前言 

呵呵 大概是由于最近的这个 “Apache Log4j被曝存在严重高危险级别远程代码执行漏洞” 

昨天晚上 编译了一下 logging-log4j2-log4j-2.15.0-rc2, 项目需要一个 toolchain.xml 的一个配置, 里面需要配置为 jdk9 

因此 我的项目配置的 jdk 为 jdk9 

然后 idea 里面默认的 字节码 级别为 jdk8 

因此 就造成了这个 基于 jdk9 编译的 jdk8 的字节码 

进而 造成了这里的问题 

测试用例

首先 基于 logging-log4j2-log4j-2.15.0-rc2 项目 打包, 基于 jdk9 编译 jdk8 版本的字节码 

然后 项目中导入 log4j-core 的依赖, 并执行 

/**
 * Test01Log4j2Dot15
 *
 * @author Jerry.X.He <970655147@qq.com>
 * @version 1.0
 * @date 2021-12-10 21:11
 */
public class Test01Log4j2Dot15 implements Cloneable {
 
    // logger
    private static Logger logger = LogManager.getLogger();
 
    private int x1;
    private int x2;
    private int x3;
    private int x4;
    private int x5;
    private int x6;
 
    // Test01Log4j2Dot15
    public static void main(String[] args) throws Exception {
 
        logger.error("xxx");
 
        ByteBuffer buf = ByteBuffer.allocateDirect(12);
        System.gc();
        buf.clear();
 
    }
 
}

报错如下 

Exception in thread "main" java.lang.NoSuchMethodError: java.nio.ByteBuffer.clear()Ljava/nio/ByteBuffer;
	at org.apache.logging.log4j.core.appender.OutputStreamManager.flushBuffer(OutputStreamManager.java:286)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.flush(OutputStreamManager.java:294)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.closeOutputStream(OutputStreamManager.java:299)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.releaseSub(OutputStreamManager.java:122)
	at org.apache.logging.log4j.core.appender.AbstractManager.stop(AbstractManager.java:86)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.stop(AbstractOutputStreamAppender.java:162)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.stop(AbstractOutputStreamAppender.java:156)
	at org.apache.logging.log4j.core.config.AbstractConfiguration.stop(AbstractConfiguration.java:399)
	at org.apache.logging.log4j.core.AbstractLifeCycle.stop(AbstractLifeCycle.java:136)
	at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:631)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:699)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:716)
	at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:270)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:155)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:47)
	at org.apache.logging.log4j.LogManager.getContext(LogManager.java:196)
	at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:599)
	at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:585)
	at com.hx.test.Test01Log4j2Dot15.<clinit>(Test01Log4j2Dot15.java:19)

class 版本为 52, 对应于 jdk8  

报错的方法调用的地方, clear 方法, 注意 signature 为 ()Ljava/nio/ByteBuffer; 

在 jdk8 中 Buffer.clear 方法如下, 是 final 的, 并且返回值为 Buffer 

在 jdk9 中 Buffer.clear 修改为了 非final, 并且 ByteBuffer 重写了 clear 方法, 返回类型更新为了 ByteBuffer 

基于 HotSpotVM 的调试 

拿到这个 "基于 jdk9 编译的 jdk8版本 的字节码", 拿到 jdk8 中去执行, 报错 便是上面提到的日志 

Exception in thread "main" java.lang.NoSuchMethodError: java.nio.ByteBuffer.clear()Ljava/nio/ByteBuffer;
	at org.apache.logging.log4j.core.appender.OutputStreamManager.flushBuffer(OutputStreamManager.java:286)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.flush(OutputStreamManager.java:294)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.closeOutputStream(OutputStreamManager.java:299)
	at org.apache.logging.log4j.core.appender.OutputStreamManager.releaseSub(OutputStreamManager.java:122)
	at org.apache.logging.log4j.core.appender.AbstractManager.stop(AbstractManager.java:86)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.stop(AbstractOutputStreamAppender.java:162)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.stop(AbstractOutputStreamAppender.java:156)
	at org.apache.logging.log4j.core.config.AbstractConfiguration.stop(AbstractConfiguration.java:399)
	at org.apache.logging.log4j.core.AbstractLifeCycle.stop(AbstractLifeCycle.java:136)
	at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:631)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:699)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:716)
	at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:270)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:155)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:47)
	at org.apache.logging.log4j.LogManager.getContext(LogManager.java:196)
	at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:599)
	at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:585)
	at com.hx.test.Test01Log4j2Dot15.<clinit>(Test01Log4j2Dot15.java:19)

大致的原因如下, 在 ByteBuffer 以及其 基类中 lookup 方法 ByteBuffer clear(), 结果没有找到 

然后 抛出了 NoSuchMethodError 

如果是在 jdk9 下面执行就不会有问题了 

另外需要使用 jdk8 来编译 jdk8 版本的字节码 

这样 就可以在 jdk8 上面跑了, 执行效果如下 

其实就是编译的时候 log4j 项目需要 toolchain.xml  配置 jdk9 的这个提示把我误导了 

当然 目前不知道 这个提示是在什么场景下才有用 

完