http://nexus.sonatype.org/oss-repository-hosting.html/ST4: StringTemplate is a java template engine for generating source code, web pages, emails, or any other formatted text output. StringTemplate is particularly good at multi-targeted code generators, multiple site skins, and internationalization/localization. It evolved over years of effort developing jGuru.com. StringTemplate also powers the ANTLR 3 and 4 code generator. Its distinguishing characteristic is that unlike other engines, it strictly enforces model-view separation. Strict separation makes websites and code generators more flexible and maintainable; it also provides an excellent defense against malicious template authors. 
class org.stringtemplate.v4.Interpreter$1 extends java.util.HashSet<java.lang.String>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: org.stringtemplate.v4.Interpreter$1
  super_class: java.util.HashSet
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // org.stringtemplate.v4.Interpreter$1 this
         0: .line 63
            aload 0 /* this */
            invokespecial java.util.HashSet.<init>:()V
            aload 0 /* this */
            ldc "i"
            invokevirtual org.stringtemplate.v4.Interpreter$1.add:(Ljava/lang/Object;)Z
            pop
            aload 0 /* this */
            ldc "i0"
            invokevirtual org.stringtemplate.v4.Interpreter$1.add:(Ljava/lang/Object;)Z
            pop
            return
        end local 0 // org.stringtemplate.v4.Interpreter$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/stringtemplate/v4/Interpreter$1;
}
Signature: Ljava/util/HashSet<Ljava/lang/String;>;
SourceFile: "Interpreter.java"
EnclosingMethod: org.stringtemplate.v4.Interpreter
NestHost: org.stringtemplate.v4.Interpreter
InnerClasses:
  org.stringtemplate.v4.Interpreter$1