Is a jni implementation of the apangin/jattach utility
The utility to send commands to remote JVM via Dynamic Attach mechanism.
All-in-one jmap + jstack + jcmd + jinfo functionality in a single tiny program.
No installed JDK required, works with just JRE.
This is the lightweight native version of HotSpot Attach API
https://docs.oracle.com/javase/8/docs/jdk/api/attach/spec/
int responseCode = Jattach.exec(pid, command, option1, option2, option3, buffer);
Where buffer - DirectByteBuffer in which the response will be written, if null, the result will be written to standard stdout. Use ByteBuffer.allocateDirect(bufferSize).
- load : load agent library
- properties : print system properties
- agentProperties : print agent properties
- datadump : show heap and thread summary. Issue: the result of this command is written to standard stdout, even if
bufferis not null - threaddump : dump all stack traces (like jstack)
- dumpheap : dump heap (like jmap)
- inspectheap : heap histogram (like jmap -histo)
- setflag : modify manageable VM flag
- printflag : print VM flag
- jcmd : execute jcmd command
int responseCode = Jattach.exec(pid, "load", "path to jvmti agent", "true" | "false", "[options]", buffer);
Where true means that the path is absolute, false - the path is relative, options are passed to the agent.
int responseCode = Jattach.exec(pid, "load", "instrument", "false", "agentJar.jar", null);
ByteBuffer buffer = ByteBuffer.allocateDirect(8192);
int responseCode = Jattach.exec(pid, "properties", null, null, null, buffer);
$ java -jar jattach.jar <pid> <command> [options] [--buffersize <size>]