Where does the "java" in the string constant pool come from?

String s1 = new StringBuilder().append("").append("").toString();
System.out.println(s1.intern() == s1);
String s2 = new StringBuilder().append("ja").append("va").toString();
System.out.println(s2.intern() == s2);

output results

true
false

I can understand the first true, but why is the second false? the book says that "java" appeared before stringbuilder.tostring (). After I check it on javap

Constant pool:
   -sharp1 = Methodref          -sharp14.-sharp27        // java/lang/Object."<init>":()V
   -sharp2 = Class              -sharp28            // java/lang/StringBuilder
   -sharp3 = Methodref          -sharp2.-sharp27         // java/lang/StringBuilder."<init>":()V
   -sharp4 = String             -sharp29            // 
   -sharp5 = Methodref          -sharp2.-sharp30         // java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
   -sharp6 = String             -sharp31            // 
   -sharp7 = Methodref          -sharp2.-sharp32         // java/lang/StringBuilder.toString:()Ljava/lang/String;
   -sharp8 = Fieldref           -sharp33.-sharp34        // java/lang/System.out:Ljava/io/PrintStream;
   -sharp9 = Methodref          -sharp35.-sharp36        // java/lang/String.intern:()Ljava/lang/String;
  -sharp10 = Methodref          -sharp37.-sharp38        // java/io/PrintStream.println:(Z)V
  -sharp11 = String             -sharp39            // ja
  -sharp12 = String             -sharp40            // va
  -sharp13 = Class              -sharp41            // TestPool
  -sharp14 = Class              -sharp42            // java/lang/Object
  -sharp15 = Utf8               <init>
  -sharp16 = Utf8               ()V
  -sharp17 = Utf8               Code
  -sharp18 = Utf8               LineNumberTable
  -sharp19 = Utf8               main
  -sharp20 = Utf8               ([Ljava/lang/String;)V
  -sharp21 = Utf8               StackMapTable
  -sharp22 = Class              -sharp43            // "[Ljava/lang/String;"
  -sharp23 = Class              -sharp44            // java/lang/String
  -sharp24 = Class              -sharp45            // java/io/PrintStream
  -sharp25 = Utf8               SourceFile
  -sharp26 = Utf8               TestPool.java
  -sharp27 = NameAndType        -sharp15:-sharp16        // "<init>":()V
  -sharp28 = Utf8               java/lang/StringBuilder
  -sharp29 = Utf8               
  -sharp30 = NameAndType        -sharp46:-sharp47        // append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
  -sharp31 = Utf8               
  -sharp32 = NameAndType        -sharp48:-sharp49        // toString:()Ljava/lang/String;
  -sharp33 = Class              -sharp50            // java/lang/System
  -sharp34 = NameAndType        -sharp51:-sharp52        // out:Ljava/io/PrintStream;
  -sharp35 = Class              -sharp44            // java/lang/String
  -sharp36 = NameAndType        -sharp53:-sharp49        // intern:()Ljava/lang/String;
  -sharp37 = Class              -sharp45            // java/io/PrintStream
  -sharp38 = NameAndType        -sharp54:-sharp55        // println:(Z)V
  -sharp39 = Utf8               ja
  -sharp40 = Utf8               va
  -sharp41 = Utf8               TestPool
  -sharp42 = Utf8               java/lang/Object
  -sharp43 = Utf8               [Ljava/lang/String;
  -sharp44 = Utf8               java/lang/String
  -sharp45 = Utf8               java/io/PrintStream
  -sharp46 = Utf8               append
  -sharp47 = Utf8               (Ljava/lang/String;)Ljava/lang/StringBuilder;
  -sharp48 = Utf8               toString
  -sharp49 = Utf8               ()Ljava/lang/String;
  -sharp50 = Utf8               java/lang/System
  -sharp51 = Utf8               out
  -sharp52 = Utf8               Ljava/io/PrintStream;
  -sharp53 = Utf8               intern
  -sharp54 = Utf8               println
  -sharp55 = Utf8               (Z)V

Excuse me, where is the literal amount of the original "java"?

Java

Mar.12,2021