Comparison of different constructor strategies.

01_test.scala

package test

abstract class Cat1(val name: String, val age: Int)
class Tabby1(override val name: String, override val age: Int) extends Cat1(name, age)

abstract class Cat2(val name: String, val age: Int)
class Tabby2(name0: String, age0: Int) extends Cat2(name0, age0)

02_Tabby.diff

2,15c2,3
< public class test.Tabby1 extends test.Cat1 {
<   public java.lang.String name();
<     Code:
<        0: aload_0       
<        1: invokespecial #12                 // Method test/Cat1.name:()Ljava/lang/String;
<        4: areturn       
< 
<   public int age();
<     Code:
<        0: aload_0       
<        1: invokespecial #18                 // Method test/Cat1.age:()I
<        4: ireturn       
< 
<   public test.Tabby1(java.lang.String, int);
---
> public class test.Tabby2 extends test.Cat2 {
>   public test.Tabby2(java.lang.String, int);
20c8
<        3: invokespecial #22                 // Method test/Cat1."<init>":(Ljava/lang/String;I)V
---
>        3: invokespecial #12                 // Method test/Cat2."<init>":(Ljava/lang/String;I)V

03_Cat1.out

Compiled from "test.scala"
public abstract class test.Cat1 {
  private final java.lang.String name;

  private final int age;

  public java.lang.String name();
    Code:
       0: aload_0       
       1: getfield      #15                 // Field name:Ljava/lang/String;
       4: areturn       

  public int age();
    Code:
       0: aload_0       
       1: getfield      #20                 // Field age:I
       4: ireturn       

  public test.Cat1(java.lang.String, int);
    Code:
       0: aload_0       
       1: aload_1       
       2: putfield      #15                 // Field name:Ljava/lang/String;
       5: aload_0       
       6: iload_2       
       7: putfield      #20                 // Field age:I
      10: aload_0       
      11: invokespecial #25                 // Method java/lang/Object."<init>":()V
      14: return        
}

04_Cat2.out

Compiled from "test.scala"
public abstract class test.Cat2 {
  private final java.lang.String name;

  private final int age;

  public java.lang.String name();
    Code:
       0: aload_0       
       1: getfield      #15                 // Field name:Ljava/lang/String;
       4: areturn       

  public int age();
    Code:
       0: aload_0       
       1: getfield      #20                 // Field age:I
       4: ireturn       

  public test.Cat2(java.lang.String, int);
    Code:
       0: aload_0       
       1: aload_1       
       2: putfield      #15                 // Field name:Ljava/lang/String;
       5: aload_0       
       6: iload_2       
       7: putfield      #20                 // Field age:I
      10: aload_0       
      11: invokespecial #25                 // Method java/lang/Object."<init>":()V
      14: return        
}

05_Tabby1.out

Compiled from "test.scala"
public class test.Tabby1 extends test.Cat1 {
  public java.lang.String name();
    Code:
       0: aload_0       
       1: invokespecial #12                 // Method test/Cat1.name:()Ljava/lang/String;
       4: areturn       

  public int age();
    Code:
       0: aload_0       
       1: invokespecial #18                 // Method test/Cat1.age:()I
       4: ireturn       

  public test.Tabby1(java.lang.String, int);
    Code:
       0: aload_0       
       1: aload_1       
       2: iload_2       
       3: invokespecial #22                 // Method test/Cat1."<init>":(Ljava/lang/String;I)V
       6: return        
}

06_Tabby2.out

Compiled from "test.scala"
public class test.Tabby2 extends test.Cat2 {
  public test.Tabby2(java.lang.String, int);
    Code:
       0: aload_0       
       1: aload_1       
       2: iload_2       
       3: invokespecial #12                 // Method test/Cat2."<init>":(Ljava/lang/String;I)V
       6: return        
}