Calling a static method inside a class in jar file

Question

I want to execute specific method inside class in jar file which is don't have main method, with java command I tried java -cp classes.jar com.example.test.Application but I get this error Error: Could not find or load main class After decompile jar file I have found Application class inside it is there any way to call a static function inside Application class in a jar file?

you cannot do this. write a test case. thats what tests are for isn't it? — pvpkiran, Sep 30 '19 at 13:12
create another class with a main method that calls your static method. — Maurice Perry, Sep 30 '19 at 13:14
@MauricePerry this is jar file how can i create another class with main method? — Daniel.V, Sep 30 '19 at 13:17
What is the ultimate goal? You create a new Java class that calls the method in question. — Dave Newton, Sep 30 '19 at 13:19
@Daniel.V just because you can't create a main method in that jar, doesn't mean you can't create a main methodµ — Stultuske, Sep 30 '19 at 13:20
As other comments have said, this is not something you should do or want to do. You could write a main class which calls the static function in question reflectivly. An alternative which is really hacky and will cause initialization problems is to call your static function from a static initializer. — PiRocks, Sep 30 '19 at 13:26

i.bondarenko · Accepted Answer · 2019-09-30T13:34:50.590

You could use Jshell:

$ jshell --class-path  ~/.m2/repository/org/apache/commons/commons-lang3/3.9/commons-lang3-3.9.jar
|  Welcome to JShell -- Version 11.0.4
|  For an introduction type: /help intro

jshell> org.apache.commons.lang3.StringUtils.join("a", "b", "c")
$1 ==> "abc"

Or create a java class with main compile it and run with java:

Test.java:

class Test {
    public static void main(String[] args) {
        String result = org.apache.commons.lang3.StringUtils.join("a", "b", "c");
        System.out.println(result);
    }
}

Compile and run:

$ javac -cp /path/to/jar/commons-lang3-3.9.jar  Test.java
$ java -cp /path/to/jar/commons-lang3-3.9.jar:.  Test
abc

Calling a static method inside a class in jar file

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