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 
final class org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction<T, V> implements org.eclipse.collections.api.block.function.Function<T, V>
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction
  super_class: java.lang.Object
{
  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 1

  private final org.eclipse.collections.api.block.function.Function<? super T, ? extends V> function;
    descriptor: Lorg/eclipse/collections/api/block/function/Function;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL
    Signature: Lorg/eclipse/collections/api/block/function/Function<-TT;+TV;>;

  private final V nullValue;
    descriptor: Ljava/lang/Object;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL
    Signature: TV;

  private void <init>(org.eclipse.collections.api.block.function.Function<? super T, ? extends V>, );
    descriptor: (Lorg/eclipse/collections/api/block/function/Function;Ljava/lang/Object;)V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction this
        start local 1 // org.eclipse.collections.api.block.function.Function function
        start local 2 // java.lang.Object nullValue
         0: .line 765
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 767
            aload 0 /* this */
            aload 1 /* function */
            putfield org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction.function:Lorg/eclipse/collections/api/block/function/Function;
         2: .line 768
            aload 0 /* this */
            aload 2 /* nullValue */
            putfield org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction.nullValue:Ljava/lang/Object;
         3: .line 769
            return
        end local 2 // java.lang.Object nullValue
        end local 1 // org.eclipse.collections.api.block.function.Function function
        end local 0 // org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    4     0       this  Lorg/eclipse/collections/impl/block/factory/Functions$NullSafeFunction<TT;TV;>;
            0    4     1   function  Lorg/eclipse/collections/api/block/function/Function<-TT;+TV;>;
            0    4     2  nullValue  TV;
    Signature: (Lorg/eclipse/collections/api/block/function/Function<-TT;+TV;>;TV;)V
    MethodParameters:
           Name  Flags
      function   
      nullValue  

  public V valueOf();
    descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction this
        start local 1 // java.lang.Object object
         0: .line 774
            aload 1 /* object */
            ifnonnull 1
            aload 0 /* this */
            getfield org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction.nullValue:Ljava/lang/Object;
            goto 2
      StackMap locals:
      StackMap stack:
         1: aload 0 /* this */
            getfield org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction.function:Lorg/eclipse/collections/api/block/function/Function;
            aload 1 /* object */
            invokeinterface org.eclipse.collections.api.block.function.Function.valueOf:(Ljava/lang/Object;)Ljava/lang/Object;
      StackMap locals:
      StackMap stack: java.lang.Object
         2: areturn
        end local 1 // java.lang.Object object
        end local 0 // org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    3     0    this  Lorg/eclipse/collections/impl/block/factory/Functions$NullSafeFunction<TT;TV;>;
            0    3     1  object  TT;
    Signature: (TT;)TV;
    MethodParameters:
        Name  Flags
      object  
}
Signature: <T:Ljava/lang/Object;V:Ljava/lang/Object;>Ljava/lang/Object;Lorg/eclipse/collections/api/block/function/Function<TT;TV;>;
SourceFile: "Functions.java"
NestHost: org.eclipse.collections.impl.block.factory.Functions
InnerClasses:
  private final NullSafeFunction = org.eclipse.collections.impl.block.factory.Functions$NullSafeFunction of org.eclipse.collections.impl.block.factory.Functions