arthas/arthas-tutorials-en/command/sc/sc.md

Search classes loaded by JVM.

sc{{}} stands for search class. This command can search all possible classes loaded by JVM and show their information. The supported options are: [d]{{}} 、[E]{{}} 、[f]{{}} and [x:]{{}} .

Supported Options

Name	Specification
class-pattern	pattern for the class name
method-pattern	pattern for the method name
[d]{{}}	print the details of the current class, including its code source, class specification, its class loader and so on. If a class is loaded by more than one class loader, then the class details will be printed several times
[E]{{}}	turn on regex match, the default behavior is wildcards match
[f]{{}}	print the fields info of the current class, MUST be used with -d{{}} together
[x:]{{}}	specify the depth of recursive traverse the static fields, the default value is '0' - equivalent to use toString{{}} to output
[c:]{{}}	The hash code of the special class's classLoader
[classLoaderClass:]{{}}	The class name of the ClassLoader that executes the expression.
[n:]{{}}	Maximum number of matching classes with details (100 by default)

sc command Docs

class-patten supports full qualified class name, e.g. com.taobao.test.AAA and com/taobao/test/AAA. It also supports the format of 'com/taobao/test/AAA', so that it is convenient to directly copy class name from the exception stack trace without replacing '/' to '.'.

> sc{{}} turns on matching sub-class match by default, that is, sc{{}} will also search the sub classes of the target class too. If exact-match is desired, pls. use options disable-sub-class true{{}} .

Usage

• Wildcards match search sc demo.*{{execute T2}}

• View class details sc -d demo.MathGame{{execute T2}}

• Specify classLoader Note that the hashcode changes, you need to check the current ClassLoader information first, and extract the hashcode corresponding to the ClassLoader.
  if you use-c{{}} , you have to manually type hashcode by -c <hashcode>{{}} .
  For classloader with only one instance, it can be specified by --classLoaderClass{{}} using class name, which is more convenient to use.

sc --classLoaderClass jdk.internal.loader.ClassLoaders$AppClassLoader -d demo*{{execute T2}}

• PS: Here the classLoaderClass in java 8 is sun.misc.Launcher$AppClassLoader, while in java 11 it's jdk.internal.loader.ClassLoaders$AppClassLoader. Currently killercoda using java 11.

The value of --classloaderclass{{}} is the class name of classloader. It can only work when it matches a unique classloader instance. The purpose is to facilitate the input of general commands. However, -c <hashcode>{{}} is dynamic.

• View class fields sc -d -f demo.MathGame{{execute T2}}