https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
public interface com.google.common.collect.Interner<E>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: com.google.common.collect.Interner
  super_class: java.lang.Object
{
  public abstract E intern();
    descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (TE;)TE;
    RuntimeInvisibleAnnotations: 
      com.google.errorprone.annotations.CanIgnoreReturnValue()
    MethodParameters:
        Name  Flags
      sample  
}
Signature: <E:Ljava/lang/Object;>Ljava/lang/Object;
SourceFile: "Interner.java"
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.Beta()
      com.google.common.annotations.GwtIncompatible()