Java verbose class loading

Question

I am trying to list the order in which the Java class loader is loading my classes. if I use -verbose parameter it will list every single interface/class it loads, including tons of interfaces such as Serializable, exceptions etc. Is there a way to tweak this output so it only shows which classes are loaded in the class my main method is defined?

Solution 1

I guess your best bet is to do the following:

• Output some fixed text once your main method starts and right before it ends.
• Pipe the verbose output into a file
• Use things like less or grep to find the classes loaded between the two tags from the main method.

There's a similar question and some answers here: Is there a way to get which classes a ClassLoader has loaded?

Did you try -verbose:class?

Solution 2

Here's a sed expression that will parse the output of java -verbose:class to produce pairs of loaded class name and its jar file. You can further pipe through a sort to get unique jar files. For example,

java -verbose:class -version 2>/dev/null |
  sed -ne 's/\[Loaded \(.\+\) from \(.\+\)\]/\2/p' | 
  sort -u

outputs

/usr/local/jdk1.7.0_67/jre/lib/rt.jar

Comments

[Renato]

In case anyone is wondering where this is documented: docs.oracle.com/en/java/javase/11/tools/java.html