A DESCRIPTION OF THE PROBLEM :
> Task :javadoc
javadoc: error - An internal exception has occurred.
        (java.lang.StringIndexOutOfBoundsException: String index out of range: -2)
Please file a bug against the javadoc tool via the Java bug reporting page
(http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com)
for duplicates. Include error messages and the following diagnostic in your report. Thank you.
java.lang.StringIndexOutOfBoundsException: String index out of range: -2
        at java.base/java.lang.String.substring(String.java:1841)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.simpleBinaryName(ClassReader.java:1510)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readEnclosingMethodAttr(ClassReader.java:1482)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader$10.read(ClassReader.java:1206)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readAttrs(ClassReader.java:1586)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readClassAttrs(ClassReader.java:1600)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readClass(ClassReader.java:2707)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readClassBuffer(ClassReader.java:2808)
        at jdk.compiler/com.sun.tools.javac.jvm.ClassReader.readClassFile(ClassReader.java:2821)
        at jdk.compiler/com.sun.tools.javac.code.ClassFinder.fillIn(ClassFinder.java:359)
        at jdk.compiler/com.sun.tools.javac.code.ClassFinder.complete(ClassFinder.java:291)
        at jdk.compiler/com.sun.tools.javac.code.Symbol.complete(Symbol.java:642)
        at jdk.compiler/com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1326)
        at jdk.compiler/com.sun.tools.javac.code.Symbol.apiComplete(Symbol.java:648)
        at jdk.compiler/com.sun.tools.javac.code.Symbol$TypeSymbol.getEnclosedElements(Symbol.java:819)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getItems0(Utils.java:2439)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getItems0(Utils.java:2434)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.recursiveGetItems(Utils.java:2422)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils$17.visitPackage(Utils.java:2408)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils$17.visitPackage(Utils.java:2404)
        at jdk.compiler/com.sun.tools.javac.code.Symbol$PackageSymbol.accept(Symbol.java:1177)
        at java.compiler@11.0.1/javax.lang.model.util.AbstractElementVisitor6.visit(AbstractElementVisitor6.java:106)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getItems(Utils.java:2417)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getClasses(Utils.java:2169)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.util.Utils.getAllClasses(Utils.java:2330)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.builders.ConstantsSummaryBuilder.hasConstantField(ConstantsSummaryBuilder.java:248)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.builders.ConstantsSummaryBuilder.buildContents(ConstantsSummaryBuilder.java:160)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.builders.ConstantsSummaryBuilder.buildConstantSummary(ConstantsSummaryBuilder.java:144)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.builders.ConstantsSummaryBuilder.build(ConstantsSummaryBuilder.java:132)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.AbstractDoclet.generateOtherFiles(AbstractDoclet.java:228)
        at jdk.javadoc/jdk.javadoc.internal.doclets.formats.html.HtmlDoclet.generateOtherFiles(HtmlDoclet.java:115)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.AbstractDoclet.startGeneration(AbstractDoclet.java:213)
        at jdk.javadoc/jdk.javadoc.internal.doclets.toolkit.AbstractDoclet.run(AbstractDoclet.java:114)
        at jdk.javadoc/jdk.javadoc.doclet.StandardDoclet.run(StandardDoclet.java:72)
        at jdk.javadoc/jdk.javadoc.internal.tool.Start.parseAndExecute(Start.java:582)
        at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:431)
        at jdk.javadoc/jdk.javadoc.internal.tool.Start.begin(Start.java:344)
        at jdk.javadoc/jdk.javadoc.internal.tool.Main.execute(Main.java:63)
        at jdk.javadoc/jdk.javadoc.internal.tool.Main.main(Main.java:52)