jmockit: Native library for Attach API not available in this JRE error

Question

I was trying to use jmockit to unit test my project and got the following error:

java.lang.UnsatisfiedLinkError: no attach in java.library.path
java.lang.Ill         


        

Answer 1

Dao Lam, Here are some other things to try:

• Make sure your project is using either:
  • The workspace default (That assumes that the default is your the jdk installation you just added. From the window where you added it, make sure it is checked.),
  • The jdk version, or
  • An execution Environment that uses the jdk version.
• Pull up your system's environment variables, and add this path to it: (jdk_dir)/jre/bin. (Remember, you'll have to restart Eclipse once you've saved that to get it to take).
• Close eclipse, and modify the shortcut you are using to start it to use (jdk_dir)/jre/bin.

I've found that any one of these measures will allow Eclipse to find the attach.dll.

Answer 2

Add the path to attach.dll to your PATH environment variable

Answer 3

Go to Java Build Path of your project and change the JRE System Library and make it points to the jdk instead of jre.

Answer 4

You have to set agent. You can set VM arguments if you are using eclipse and Args will be like this:

-javaagent:local path to your jmockit jar\jmockit.jar

eg: -javaagent:D:\jmockit.jar

Answer 5

It's not tools.jar that you need, but the native library file for the "Attach API": attach.dll (or the Linux/Mac equivalent, attach.so or similar). A plain JRE does not contain this library. Instead, point Eclipse to a JDK installation, which should contain the jre/bin/attach.dll file.

Answer 6

I found this issue with JDK 1.8.45 and 1.8.80 on 64-bit Windows. My solution was to copy attach.dll from the JDK's ./jre/bin directory to the ./bin. This eliminated the need for updating Eclipse and a Cygwin command line with a non-standard JAVA_HOME.

Maybe the Windows version may be ignoring the contents of the JRE directory?