arthas/tutorials/katacoda/command-sm-en/sm.md

Search method from the loaded classes.

sm stands for search method. This command can search and show method information from all loaded classes. sm can only view the methods declared on the target class, that is, methods from its parent classes are invisible.

Options

Name	Specification
class-pattern	pattern for class name
method-pattern	pattern for method name
[d]	print the details of the method
[E]	turn on regex matching while the default mode is wildcard matching
[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)

Usage

• View methods of java.lang.String:

sm java.lang.String{{execute T2}}

$ sm java.lang.String
java.lang.String-><init>
java.lang.String->equals
java.lang.String->toString
java.lang.String->hashCode
java.lang.String->compareTo
java.lang.String->indexOf
java.lang.String->valueOf
java.lang.String->checkBounds
java.lang.String->length
java.lang.String->isEmpty
java.lang.String->charAt
java.lang.String->codePointAt
java.lang.String->codePointBefore
java.lang.String->codePointCount
java.lang.String->offsetByCodePoints
java.lang.String->getChars
java.lang.String->getBytes
java.lang.String->contentEquals
java.lang.String->nonSyncContentEquals
java.lang.String->equalsIgnoreCase
java.lang.String->compareToIgnoreCase
java.lang.String->regionMatches
java.lang.String->startsWith
java.lang.String->endsWith
java.lang.String->indexOfSupplementary
java.lang.String->lastIndexOf
java.lang.String->lastIndexOfSupplementary
java.lang.String->substring
java.lang.String->subSequence
java.lang.String->concat
java.lang.String->replace
java.lang.String->matches
java.lang.String->contains
java.lang.String->replaceFirst
java.lang.String->replaceAll
java.lang.String->split
java.lang.String->join
java.lang.String->toLowerCase
java.lang.String->toUpperCase
java.lang.String->trim
java.lang.String->toCharArray
java.lang.String->format
java.lang.String->copyValueOf
java.lang.String->intern
Affect(row-cnt:44) cost in 1342 ms.

• Specify ClassLoader

Find ClassLoaderHash：

sc -d demo.MathGame | grep classLoaderHash{{execute T2}}

$ sc -d demo.MathGame | grep classLoaderHash
 classLoaderHash   70dea4e

• 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>.

$ sm -c 70dea4e demo.MathGame

For classloader with only one instance, it can be specified by --classLoaderClass using class name, which is more convenient to use.

sm --classLoaderClass sun.misc.Launcher$AppClassLoader demo.MathGame{{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 katacoda using java 8.

$ sm --classLoaderClass sun.misc.Launcher$AppClassLoader demo.MathGame
demo.MathGame <init>()V
demo.MathGame primeFactors(I)Ljava/util/List;
demo.MathGame main([Ljava/lang/String;)V
demo.MathGame run()V
demo.MathGame print(ILjava/util/List;)V
Affect(row-cnt:5) cost in 2 ms.

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 method java.lang.String#toString details:

sm -d java.lang.String toString{{execute T2}}

$ sm -d java.lang.String toString
 declaring-class  java.lang.String
 method-name      toString
 modifier         public
 annotation
 parameters
 return           java.lang.String
 exceptions

Affect(row-cnt:1) cost in 3 ms.