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. 
abstract class com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy<K, V> extends com.google.common.collect.ForwardingConcurrentMap<K, V> implements java.io.Serializable
  minor version: 0
  major version: 59
  flags: flags: (0x0420) ACC_SUPER, ACC_ABSTRACT
  this_class: com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy
  super_class: com.google.common.collect.ForwardingConcurrentMap
{
  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 3

  final com.google.common.collect.MapMakerInternalMap$Strength keyStrength;
    descriptor: Lcom/google/common/collect/MapMakerInternalMap$Strength;
    flags: (0x0010) ACC_FINAL
    Signature: Lcom/google/common/collect/MapMakerInternalMap$Strength;

  final com.google.common.collect.MapMakerInternalMap$Strength valueStrength;
    descriptor: Lcom/google/common/collect/MapMakerInternalMap$Strength;
    flags: (0x0010) ACC_FINAL
    Signature: Lcom/google/common/collect/MapMakerInternalMap$Strength;

  final com.google.common.base.Equivalence<java.lang.Object> keyEquivalence;
    descriptor: Lcom/google/common/base/Equivalence;
    flags: (0x0010) ACC_FINAL
    Signature: Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;

  final com.google.common.base.Equivalence<java.lang.Object> valueEquivalence;
    descriptor: Lcom/google/common/base/Equivalence;
    flags: (0x0010) ACC_FINAL
    Signature: Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;

  final int concurrencyLevel;
    descriptor: I
    flags: (0x0010) ACC_FINAL

  transient java.util.concurrent.ConcurrentMap<K, V> delegate;
    descriptor: Ljava/util/concurrent/ConcurrentMap;
    flags: (0x0080) ACC_TRANSIENT
    Signature: Ljava/util/concurrent/ConcurrentMap<TK;TV;>;

  void <init>(com.google.common.collect.MapMakerInternalMap$Strength, com.google.common.collect.MapMakerInternalMap$Strength, com.google.common.base.Equivalence<java.lang.Object>, com.google.common.base.Equivalence<java.lang.Object>, int, java.util.concurrent.ConcurrentMap<K, V>);
    descriptor: (Lcom/google/common/collect/MapMakerInternalMap$Strength;Lcom/google/common/collect/MapMakerInternalMap$Strength;Lcom/google/common/base/Equivalence;Lcom/google/common/base/Equivalence;ILjava/util/concurrent/ConcurrentMap;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=7, args_size=7
        start local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
        start local 1 // com.google.common.collect.MapMakerInternalMap$Strength keyStrength
        start local 2 // com.google.common.collect.MapMakerInternalMap$Strength valueStrength
        start local 3 // com.google.common.base.Equivalence keyEquivalence
        start local 4 // com.google.common.base.Equivalence valueEquivalence
        start local 5 // int concurrencyLevel
        start local 6 // java.util.concurrent.ConcurrentMap delegate
         0: .line 2862
            aload 0 /* this */
            invokespecial com.google.common.collect.ForwardingConcurrentMap.<init>:()V
         1: .line 2869
            aload 0 /* this */
            aload 1 /* keyStrength */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.keyStrength:Lcom/google/common/collect/MapMakerInternalMap$Strength;
         2: .line 2870
            aload 0 /* this */
            aload 2 /* valueStrength */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.valueStrength:Lcom/google/common/collect/MapMakerInternalMap$Strength;
         3: .line 2871
            aload 0 /* this */
            aload 3 /* keyEquivalence */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.keyEquivalence:Lcom/google/common/base/Equivalence;
         4: .line 2872
            aload 0 /* this */
            aload 4 /* valueEquivalence */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.valueEquivalence:Lcom/google/common/base/Equivalence;
         5: .line 2873
            aload 0 /* this */
            iload 5 /* concurrencyLevel */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.concurrencyLevel:I
         6: .line 2874
            aload 0 /* this */
            aload 6 /* delegate */
            putfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:Ljava/util/concurrent/ConcurrentMap;
         7: .line 2875
            return
        end local 6 // java.util.concurrent.ConcurrentMap delegate
        end local 5 // int concurrencyLevel
        end local 4 // com.google.common.base.Equivalence valueEquivalence
        end local 3 // com.google.common.base.Equivalence keyEquivalence
        end local 2 // com.google.common.collect.MapMakerInternalMap$Strength valueStrength
        end local 1 // com.google.common.collect.MapMakerInternalMap$Strength keyStrength
        end local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
      LocalVariableTable:
        Start  End  Slot              Name  Signature
            0    8     0              this  Lcom/google/common/collect/MapMakerInternalMap$AbstractSerializationProxy<TK;TV;>;
            0    8     1       keyStrength  Lcom/google/common/collect/MapMakerInternalMap$Strength;
            0    8     2     valueStrength  Lcom/google/common/collect/MapMakerInternalMap$Strength;
            0    8     3    keyEquivalence  Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;
            0    8     4  valueEquivalence  Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;
            0    8     5  concurrencyLevel  I
            0    8     6          delegate  Ljava/util/concurrent/ConcurrentMap<TK;TV;>;
    Signature: (Lcom/google/common/collect/MapMakerInternalMap$Strength;Lcom/google/common/collect/MapMakerInternalMap$Strength;Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;Lcom/google/common/base/Equivalence<Ljava/lang/Object;>;ILjava/util/concurrent/ConcurrentMap<TK;TV;>;)V
    MethodParameters:
                  Name  Flags
      keyStrength       
      valueStrength     
      keyEquivalence    
      valueEquivalence  
      concurrencyLevel  
      delegate          

  protected java.util.concurrent.ConcurrentMap<K, V> delegate();
    descriptor: ()Ljava/util/concurrent/ConcurrentMap;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
         0: .line 2879
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:Ljava/util/concurrent/ConcurrentMap;
            areturn
        end local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/collect/MapMakerInternalMap$AbstractSerializationProxy<TK;TV;>;
    Signature: ()Ljava/util/concurrent/ConcurrentMap<TK;TV;>;

  void writeMapTo(java.io.ObjectOutputStream);
    descriptor: (Ljava/io/ObjectOutputStream;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=4, args_size=2
        start local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
        start local 1 // java.io.ObjectOutputStream out
         0: .line 2883
            aload 1 /* out */
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:Ljava/util/concurrent/ConcurrentMap;
            invokeinterface java.util.concurrent.ConcurrentMap.size:()I
            invokevirtual java.io.ObjectOutputStream.writeInt:(I)V
         1: .line 2884
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:Ljava/util/concurrent/ConcurrentMap;
            invokeinterface java.util.concurrent.ConcurrentMap.entrySet:()Ljava/util/Set;
            invokeinterface java.util.Set.iterator:()Ljava/util/Iterator;
            astore 3
            goto 5
      StackMap locals: com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy java.io.ObjectOutputStream top java.util.Iterator
      StackMap stack:
         2: aload 3
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast java.util.Map$Entry
            astore 2 /* entry */
        start local 2 // java.util.Map$Entry entry
         3: .line 2885
            aload 1 /* out */
            aload 2 /* entry */
            invokeinterface java.util.Map$Entry.getKey:()Ljava/lang/Object;
            invokevirtual java.io.ObjectOutputStream.writeObject:(Ljava/lang/Object;)V
         4: .line 2886
            aload 1 /* out */
            aload 2 /* entry */
            invokeinterface java.util.Map$Entry.getValue:()Ljava/lang/Object;
            invokevirtual java.io.ObjectOutputStream.writeObject:(Ljava/lang/Object;)V
        end local 2 // java.util.Map$Entry entry
         5: .line 2884
      StackMap locals:
      StackMap stack:
            aload 3
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 2
         6: .line 2888
            aload 1 /* out */
            aconst_null
            invokevirtual java.io.ObjectOutputStream.writeObject:(Ljava/lang/Object;)V
         7: .line 2889
            return
        end local 1 // java.io.ObjectOutputStream out
        end local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    8     0   this  Lcom/google/common/collect/MapMakerInternalMap$AbstractSerializationProxy<TK;TV;>;
            0    8     1    out  Ljava/io/ObjectOutputStream;
            3    5     2  entry  Ljava/util/Map$Entry<TK;TV;>;
    Exceptions:
      throws java.io.IOException
    MethodParameters:
      Name  Flags
      out   

  com.google.common.collect.MapMaker readMapMaker(java.io.ObjectInputStream);
    descriptor: (Ljava/io/ObjectInputStream;)Lcom/google/common/collect/MapMaker;
    flags: (0x0000) 
    Code:
      stack=2, locals=3, args_size=2
        start local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
        start local 1 // java.io.ObjectInputStream in
         0: .line 2893
            aload 1 /* in */
            invokevirtual java.io.ObjectInputStream.readInt:()I
            istore 2 /* size */
        start local 2 // int size
         1: .line 2894
            new com.google.common.collect.MapMaker
            dup
            invokespecial com.google.common.collect.MapMaker.<init>:()V
         2: .line 2895
            iload 2 /* size */
            invokevirtual com.google.common.collect.MapMaker.initialCapacity:(I)Lcom/google/common/collect/MapMaker;
         3: .line 2896
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.keyStrength:Lcom/google/common/collect/MapMakerInternalMap$Strength;
            invokevirtual com.google.common.collect.MapMaker.setKeyStrength:(Lcom/google/common/collect/MapMakerInternalMap$Strength;)Lcom/google/common/collect/MapMaker;
         4: .line 2897
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.valueStrength:Lcom/google/common/collect/MapMakerInternalMap$Strength;
            invokevirtual com.google.common.collect.MapMaker.setValueStrength:(Lcom/google/common/collect/MapMakerInternalMap$Strength;)Lcom/google/common/collect/MapMaker;
         5: .line 2898
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.keyEquivalence:Lcom/google/common/base/Equivalence;
            invokevirtual com.google.common.collect.MapMaker.keyEquivalence:(Lcom/google/common/base/Equivalence;)Lcom/google/common/collect/MapMaker;
         6: .line 2899
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.concurrencyLevel:I
            invokevirtual com.google.common.collect.MapMaker.concurrencyLevel:(I)Lcom/google/common/collect/MapMaker;
         7: .line 2894
            areturn
        end local 2 // int size
        end local 1 // java.io.ObjectInputStream in
        end local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    8     0  this  Lcom/google/common/collect/MapMakerInternalMap$AbstractSerializationProxy<TK;TV;>;
            0    8     1    in  Ljava/io/ObjectInputStream;
            1    8     2  size  I
    Exceptions:
      throws java.io.IOException
    MethodParameters:
      Name  Flags
      in    

  void readEntries(java.io.ObjectInputStream);
    descriptor: (Ljava/io/ObjectInputStream;)V
    flags: (0x0000) 
    Code:
      stack=3, locals=4, args_size=2
        start local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
        start local 1 // java.io.ObjectInputStream in
         0: .line 2905
      StackMap locals:
      StackMap stack:
            aload 1 /* in */
            invokevirtual java.io.ObjectInputStream.readObject:()Ljava/lang/Object;
            astore 2 /* key */
        start local 2 // java.lang.Object key
         1: .line 2906
            aload 2 /* key */
            ifnonnull 3
         2: .line 2907
            goto 6
         3: .line 2909
      StackMap locals: java.lang.Object
      StackMap stack:
            aload 1 /* in */
            invokevirtual java.io.ObjectInputStream.readObject:()Ljava/lang/Object;
            astore 3 /* value */
        start local 3 // java.lang.Object value
         4: .line 2910
            aload 0 /* this */
            getfield com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:Ljava/util/concurrent/ConcurrentMap;
            aload 2 /* key */
            aload 3 /* value */
            invokeinterface java.util.concurrent.ConcurrentMap.put:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
            pop
        end local 3 // java.lang.Object value
        end local 2 // java.lang.Object key
         5: .line 2904
            goto 0
         6: .line 2912
      StackMap locals:
      StackMap stack:
            return
        end local 1 // java.io.ObjectInputStream in
        end local 0 // com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    7     0   this  Lcom/google/common/collect/MapMakerInternalMap$AbstractSerializationProxy<TK;TV;>;
            0    7     1     in  Ljava/io/ObjectInputStream;
            1    5     2    key  TK;
            4    5     3  value  TV;
    Exceptions:
      throws java.io.IOException, java.lang.ClassNotFoundException
    MethodParameters:
      Name  Flags
      in    

  protected java.lang.Object delegate();
    descriptor: ()Ljava/lang/Object;
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:()Ljava/util/concurrent/ConcurrentMap;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  protected java.util.Map delegate();
    descriptor: ()Ljava/util/Map;
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy.delegate:()Ljava/util/concurrent/ConcurrentMap;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: <K:Ljava/lang/Object;V:Ljava/lang/Object;>Lcom/google/common/collect/ForwardingConcurrentMap<TK;TV;>;Ljava/io/Serializable;
SourceFile: "MapMakerInternalMap.java"
NestHost: com.google.common.collect.MapMakerInternalMap
InnerClasses:
  abstract AbstractSerializationProxy = com.google.common.collect.MapMakerInternalMap$AbstractSerializationProxy of com.google.common.collect.MapMakerInternalMap
  abstract Strength = com.google.common.collect.MapMakerInternalMap$Strength of com.google.common.collect.MapMakerInternalMap
  public abstract Entry = java.util.Map$Entry of java.util.Map