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.hash.LongAddables$PureJavaLongAddable extends java.util.concurrent.atomic.AtomicLong implements com.google.common.hash.LongAddable
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.google.common.hash.LongAddables$PureJavaLongAddable
  super_class: java.util.concurrent.atomic.AtomicLong
{
  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
         0: .line 55
            aload 0 /* this */
            invokespecial java.util.concurrent.atomic.AtomicLong.<init>:()V
            return
        end local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/hash/LongAddables$PureJavaLongAddable;

  public void increment();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
         0: .line 58
            aload 0 /* this */
            invokevirtual com.google.common.hash.LongAddables$PureJavaLongAddable.getAndIncrement:()J
            pop2
         1: .line 59
            return
        end local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/hash/LongAddables$PureJavaLongAddable;

  public void add(long);
    descriptor: (J)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
        start local 1 // long x
         0: .line 63
            aload 0 /* this */
            lload 1 /* x */
            invokevirtual com.google.common.hash.LongAddables$PureJavaLongAddable.getAndAdd:(J)J
            pop2
         1: .line 64
            return
        end local 1 // long x
        end local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/hash/LongAddables$PureJavaLongAddable;
            0    2     1     x  J
    MethodParameters:
      Name  Flags
      x     

  public long sum();
    descriptor: ()J
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
         0: .line 68
            aload 0 /* this */
            invokevirtual com.google.common.hash.LongAddables$PureJavaLongAddable.get:()J
            lreturn
        end local 0 // com.google.common.hash.LongAddables$PureJavaLongAddable this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/hash/LongAddables$PureJavaLongAddable;
}
SourceFile: "LongAddables.java"
NestHost: com.google.common.hash.LongAddables
InnerClasses:
  private final PureJavaLongAddable = com.google.common.hash.LongAddables$PureJavaLongAddable of com.google.common.hash.LongAddables