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. 
class com.google.common.io.Files$3 implements com.google.common.io.LineProcessor<java.util.List<java.lang.String>>
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.google.common.io.Files$3
  super_class: java.lang.Object
{
  final java.util.List<java.lang.String> result;
    descriptor: Ljava/util/List;
    flags: (0x0010) ACC_FINAL
    Signature: Ljava/util/List<Ljava/lang/String;>;

  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.google.common.io.Files$3 this
         0: .line 526
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 527
            aload 0 /* this */
            invokestatic com.google.common.collect.Lists.newArrayList:()Ljava/util/ArrayList;
            putfield com.google.common.io.Files$3.result:Ljava/util/List;
         2: .line 526
            return
        end local 0 // com.google.common.io.Files$3 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/google/common/io/Files$3;

  public boolean processLine(java.lang.String);
    descriptor: (Ljava/lang/String;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.io.Files$3 this
        start local 1 // java.lang.String line
         0: .line 531
            aload 0 /* this */
            getfield com.google.common.io.Files$3.result:Ljava/util/List;
            aload 1 /* line */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
         1: .line 532
            iconst_1
            ireturn
        end local 1 // java.lang.String line
        end local 0 // com.google.common.io.Files$3 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/google/common/io/Files$3;
            0    2     1  line  Ljava/lang/String;
    MethodParameters:
      Name  Flags
      line  

  public java.util.List<java.lang.String> getResult();
    descriptor: ()Ljava/util/List;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.google.common.io.Files$3 this
         0: .line 537
            aload 0 /* this */
            getfield com.google.common.io.Files$3.result:Ljava/util/List;
            areturn
        end local 0 // com.google.common.io.Files$3 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/google/common/io/Files$3;
    Signature: ()Ljava/util/List<Ljava/lang/String;>;

  public java.lang.Object getResult();
    descriptor: ()Ljava/lang/Object;
    flags: (0x1041) ACC_PUBLIC, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=1, locals=1, args_size=1
         0: .line 1
            aload 0
            invokevirtual com.google.common.io.Files$3.getResult:()Ljava/util/List;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Ljava/lang/Object;Lcom/google/common/io/LineProcessor<Ljava/util/List<Ljava/lang/String;>;>;
SourceFile: "Files.java"
EnclosingMethod: com.google.common.io.Files.readLines:(Ljava/io/File;Ljava/nio/charset/Charset;)Ljava/util/List;
NestHost: com.google.common.io.Files
InnerClasses:
  com.google.common.io.Files$3