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. 
final class com.google.common.cache.CacheLoader$FunctionToCacheLoader<K, V> extends com.google.common.cache.CacheLoader<K, V> implements java.io.Serializable
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.google.common.cache.CacheLoader$FunctionToCacheLoader
  super_class: com.google.common.cache.CacheLoader
{
  private final com.google.common.base.Function<K, V> computingFunction;
    descriptor: Lcom/google/common/base/Function;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL
    Signature: Lcom/google/common/base/Function<TK;TV;>;

  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 0

  public void <init>(com.google.common.base.Function<K, V>);
    descriptor: (Lcom/google/common/base/Function;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.cache.CacheLoader$FunctionToCacheLoader this
        start local 1 // com.google.common.base.Function computingFunction
         0: .line 159
            aload 0 /* this */
            invokespecial com.google.common.cache.CacheLoader.<init>:()V
         1: .line 160
            aload 0 /* this */
            aload 1 /* computingFunction */
            invokestatic com.google.common.base.Preconditions.checkNotNull:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast com.google.common.base.Function
            putfield com.google.common.cache.CacheLoader$FunctionToCacheLoader.computingFunction:Lcom/google/common/base/Function;
         2: .line 161
            return
        end local 1 // com.google.common.base.Function computingFunction
        end local 0 // com.google.common.cache.CacheLoader$FunctionToCacheLoader this
      LocalVariableTable:
        Start  End  Slot               Name  Signature
            0    3     0               this  Lcom/google/common/cache/CacheLoader$FunctionToCacheLoader<TK;TV;>;
            0    3     1  computingFunction  Lcom/google/common/base/Function<TK;TV;>;
    Signature: (Lcom/google/common/base/Function<TK;TV;>;)V
    MethodParameters:
                   Name  Flags
      computingFunction  

  public V load();
    descriptor: (Ljava/lang/Object;)Ljava/lang/Object;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.cache.CacheLoader$FunctionToCacheLoader this
        start local 1 // java.lang.Object key
         0: .line 165
            aload 0 /* this */
            getfield com.google.common.cache.CacheLoader$FunctionToCacheLoader.computingFunction:Lcom/google/common/base/Function;
            aload 1 /* key */
            invokestatic com.google.common.base.Preconditions.checkNotNull:(Ljava/lang/Object;)Ljava/lang/Object;
            invokeinterface com.google.common.base.Function.apply:(Ljava/lang/Object;)Ljava/lang/Object;
            areturn
        end local 1 // java.lang.Object key
        end local 0 // com.google.common.cache.CacheLoader$FunctionToCacheLoader this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/cache/CacheLoader$FunctionToCacheLoader<TK;TV;>;
            0    1     1   key  TK;
    Signature: (TK;)TV;
    MethodParameters:
      Name  Flags
      key   
}
Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>Lcom/google/common/cache/CacheLoader<TK;TV;>;Ljava/io/Serializable;
SourceFile: "CacheLoader.java"
NestHost: com.google.common.cache.CacheLoader
InnerClasses:
  private final FunctionToCacheLoader = com.google.common.cache.CacheLoader$FunctionToCacheLoader of com.google.common.cache.CacheLoader