Is this a valid use of the java ClassGraph api?

Question

Using compile 'io.github.classgraph:classgraph:4.8.65'

https://github.com/classgraph/classgraph/wiki/ClassGraph-API

Java 8

ScanResult scanResult = 
    new ClassGraph().enableAllInfo()
                    .whitelistPackages("abc1")
                    .whitelistPackages("abc2")
                    .whitelistPackages("java")
                    .scan();

When I encounter ClassInfo objects for classes from the packages abc1 or abc2 they are able to reference things like java.util.HashMap, I see them in the FieldInfo.

But when I then proceed to do scanResult.getClassInfo("java.util.HashMap"), it returns null. (following FieldInfos for other classes within the abc1 or abc2 packages do return more ClassInfo objects)

My question is, is it correct to think I would be able to get the ClassInfo objects to the java jre classes via the ClassGraph method chaining as shown above?

Added this test which fails, it surprisingly only prints one class rather than expected dozens:

package abc;

import io.github.classgraph.ScanResult;
import io.github.classgraph.ClassGraph;
import io.github.classgraph.ClassInfo;

import java.util.*;
import java.io.*;

import java.util.function.*;

import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;

@SpringJUnitConfig
@SpringBootTest(classes = {})
public class ExamplesSpec {

        @org.junit.jupiter.api.Test
        @org.junit.jupiter.api.DisplayName(value="test_for_built_in_java_jre_classes")
        public void test_on_line_42() throws Exception {

            System.out.println("test_for_built_in_java_jre_classes");
            ClassInfo found = null;
            try (
                ScanResult result = new ClassGraph().enableAllInfo().whitelistPackages("java.util").scan()
            ) {
                System.out.println("here all the classes....");
                for( ClassInfo item : result.getAllClasses()) {
                    System.out.println("here classinfo: " + item);
                }
                found = result.getClassInfo("java.util.HashMap");
            }
            assert found != null;
        }
}

The only class found is this:

here classinfo: public class java.util.zip.VFSZipFile implements java.util.zip.ZipConstants

score 1 · Accepted Answer · answered Feb 25 '20 at 06:13

Found the answer!

In the setup of the ClassGraph, in order to scan the jre provided classes, you would need to add this to the method chaining:

.enableSystemJarsAndModules()

For example:

    new ClassGraph().enableAllInfo()
                    .whitelistPackages("abc1")
                    .whitelistPackages("abc2")
                    .whitelistPackages("java")
                    .enableSystemJarsAndModules()
                    .scan();

This is detailed in the documentation found here:

https://github.com/classgraph/classgraph/wiki/API:-ClassGraph-Constructor#configuring-the-classgraph-instance

Is this a valid use of the java ClassGraph api?

1 Answers1