http://www.jooq.org/jooq: jOOQ effectively combines complex SQL, typesafety, source code generation, active records, stored procedures, advanced data types, and Java in a fluent, intuitive DSL. 
public interface org.jooq.MergeKeyStep21<R extends org.jooq.Record, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> extends org.jooq.MergeValuesStep21<R, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.jooq.MergeKeyStep21
  super_class: java.lang.Object
{
  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=3, locals=0, args_size=0
         0: .line 57
            new java.lang.Error
            dup
            ldc "Unresolved compilation problems: \n\tThe import org.jetbrains cannot be resolved\n\tNotNull cannot be resolved to a type\n\tNotNull cannot be resolved to a type\n"
            invokespecial java.lang.Error.<init>:(Ljava/lang/String;)V
            athrow
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public abstract org.jooq.MergeValuesStep21<R, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> key(org.jooq.Field<?>[]);
    descriptor: ([Lorg/jooq/Field;)Lorg/jooq/MergeValuesStep21;
    flags: (0x0481) ACC_PUBLIC, ACC_VARARGS, ACC_ABSTRACT
    Signature: ([Lorg/jooq/Field<*>;)Lorg/jooq/MergeValuesStep21<TR;TT1;TT2;TT3;TT4;TT5;TT6;TT7;TT8;TT9;TT10;TT11;TT12;TT13;TT14;TT15;TT16;TT17;TT18;TT19;TT20;TT21;>;
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()
      org.jooq.Support(value = {org.jooq.SQLDialect.CUBRID:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.DERBY:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.FIREBIRD:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.H2:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.HSQLDB:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.POSTGRES:Lorg/jooq/SQLDialect;})
    RuntimeInvisibleAnnotations: 
      NotNull()
    RuntimeInvisibleTypeAnnotations: 
      METHOD_RETURN
        NotNull()
    MethodParameters:
      Name  Flags
      keys  

  public abstract org.jooq.MergeValuesStep21<R, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21> key(java.util.Collection<? extends org.jooq.Field<?>>);
    descriptor: (Ljava/util/Collection;)Lorg/jooq/MergeValuesStep21;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: (Ljava/util/Collection<+Lorg/jooq/Field<*>;>;)Lorg/jooq/MergeValuesStep21<TR;TT1;TT2;TT3;TT4;TT5;TT6;TT7;TT8;TT9;TT10;TT11;TT12;TT13;TT14;TT15;TT16;TT17;TT18;TT19;TT20;TT21;>;
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()
      org.jooq.Support(value = {org.jooq.SQLDialect.CUBRID:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.DERBY:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.FIREBIRD:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.H2:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.HSQLDB:Lorg/jooq/SQLDialect;, org.jooq.SQLDialect.POSTGRES:Lorg/jooq/SQLDialect;})
    RuntimeInvisibleAnnotations: 
      NotNull()
    RuntimeInvisibleTypeAnnotations: 
      METHOD_RETURN
        NotNull()
    MethodParameters:
      Name  Flags
      keys  
}
Signature: <R::Lorg/jooq/Record;T1:Ljava/lang/Object;T2:Ljava/lang/Object;T3:Ljava/lang/Object;T4:Ljava/lang/Object;T5:Ljava/lang/Object;T6:Ljava/lang/Object;T7:Ljava/lang/Object;T8:Ljava/lang/Object;T9:Ljava/lang/Object;T10:Ljava/lang/Object;T11:Ljava/lang/Object;T12:Ljava/lang/Object;T13:Ljava/lang/Object;T14:Ljava/lang/Object;T15:Ljava/lang/Object;T16:Ljava/lang/Object;T17:Ljava/lang/Object;T18:Ljava/lang/Object;T19:Ljava/lang/Object;T20:Ljava/lang/Object;T21:Ljava/lang/Object;>Ljava/lang/Object;Lorg/jooq/MergeValuesStep21<TR;TT1;TT2;TT3;TT4;TT5;TT6;TT7;TT8;TT9;TT10;TT11;TT12;TT13;TT14;TT15;TT16;TT17;TT18;TT19;TT20;TT21;>;
SourceFile: "MergeKeyStep21.java"
    RuntimeVisibleAnnotations: 
      java.lang.Deprecated()