https://openjdk.java.net/ 
public interface com.sun.source.tree.PackageTree extends com.sun.source.tree.Tree
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.sun.source.tree.PackageTree
  super_class: java.lang.Object
{
  public abstract java.util.List<? extends com.sun.source.tree.AnnotationTree> getAnnotations();
    descriptor: ()Ljava/util/List;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()Ljava/util/List<+Lcom/sun/source/tree/AnnotationTree;>;

  public abstract com.sun.source.tree.ExpressionTree getPackageName();
    descriptor: ()Lcom/sun/source/tree/ExpressionTree;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
}
SourceFile: "PackageTree.java"