https://github.com/eclipse/eclipse-collections/eclipse-collections: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar 
class org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator implements java.util.Iterator<T>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator
  super_class: java.lang.Object
{
  private boolean next;
    descriptor: Z
    flags: (0x0002) ACC_PRIVATE

  final org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag this$0;
    descriptor: Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  private void <init>(org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag);
    descriptor: (Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag;)V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
         0: .line 473
            aload 0 /* this */
            aload 1
            putfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.this$0:Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag;
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 476
            aload 0 /* this */
            iconst_1
            putfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.next:Z
         2: .line 473
            return
        end local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag$SingletonIterator;
    MethodParameters:
        Name  Flags
      this$0  final

  public boolean hasNext();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
         0: .line 481
            aload 0 /* this */
            getfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.next:Z
            ireturn
        end local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag$SingletonIterator;

  public T next();
    descriptor: ()Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=1, args_size=1
        start local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
         0: .line 487
            aload 0 /* this */
            getfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.next:Z
            ifeq 3
         1: .line 489
            aload 0 /* this */
            iconst_0
            putfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.next:Z
         2: .line 490
            aload 0 /* this */
            getfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.this$0:Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag;
            getfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag.value:Ljava/lang/Object;
            areturn
         3: .line 492
      StackMap locals:
      StackMap stack:
            new java.util.NoSuchElementException
            dup
            new java.lang.StringBuilder
            dup
            ldc "i="
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 0 /* this */
            getfield org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator.next:Z
            invokevirtual java.lang.StringBuilder.append:(Z)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokespecial java.util.NoSuchElementException.<init>:(Ljava/lang/String;)V
            athrow
        end local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag$SingletonIterator;
    Signature: ()TT;

  public void remove();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
         0: .line 498
            new java.lang.UnsupportedOperationException
            dup
            ldc "Cannot remove from an ImmutableBag"
            invokespecial java.lang.UnsupportedOperationException.<init>:(Ljava/lang/String;)V
            athrow
        end local 0 // org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/eclipse/collections/impl/bag/immutable/ImmutableSingletonBag$SingletonIterator;
}
Signature: Ljava/lang/Object;Ljava/util/Iterator<TT;>;
SourceFile: "ImmutableSingletonBag.java"
NestHost: org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag
InnerClasses:
  private SingletonIterator = org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag$SingletonIterator of org.eclipse.collections.impl.bag.immutable.ImmutableSingletonBag