JavaAgent：查看版本 v5

Java自帶的調試接口，常用於運行時字節碼注入。 javaagent為一至少聲明有Premain-Class或Agent-Class屬性的jar，Premain-Class與Agent-Class為agent主類，Premain-Class類需定義public static void premain(String args, Instrumentation inst) 方法，Agent-Class類需定義public static void agentmain(String args, Instrumentation inst) 方法。 其他可選屬性為 * Can-Redefine-Classes 允許重定義類 * Can-Retransform-Classes 允許重轉換類 * Can-Set-Native-Method-Prefix 允許設置[[native method prefix]] == 相关 == * 核心接口及获取方式见 [[Instrumentation]]，JDK 内部实现见 [[InstrumentationImpl]]，底层依赖 [[JVMTI]]。 * 目前最常用的加载方式是'''运行时外部进程附加'''，不需要任何启动参数，详见 [[Instrumentation]] 的“运行时外部进程附加”一节。 Java's debug interface, commonly used for runtime class bytecode injection. javaagent is a jar file with manifest attribute Premain-Class or Agent-Class, Premain-Class attribute and Agent-Class attribute declares the agent main class of a javaagent, the class speficied by Premain-Class should declare method public static void premain(String args, Instrumentation inst) , the class specified by Agent-Class should declare method public static void agentmain(String args, Instrumentation inst) . Other optional attribute for a javaagent can be * Can-Redefine-Classes * Can-Retransform-Classes * Can-Set-Native-Method-Prefix == Related == * See [[Instrumentation]] for provided methods and how to load a javaagent, see [[InstrumentationImpl]] for default implementation at runtime, see [[JVMTI]] for underlying mechanism. * "runtime attach" is the most commonly used method to load a javaagent at present, it doesn't require any commandline arguments, see [[Instrumentation]] for more details.