mattisonchao commented on pull request #10986:
URL: https://github.com/apache/pulsar/pull/10986#issuecomment-870936897
> Did you see some measurable improvement?
>
> I am saying this because recently JVM handle string concatenation better
that using StringBuilder in same cases and forcing a concatenation strategy
sometimes it is not the best option.
>
> That said I am not against this change, but I just want to know if this is
the result of some static code analysis or it is fixing a real problem. You
know the motto 'don't fix things that are not broken
Yes, I test it in a small example. when you use a string connection inline,
the JVM will translate it to `StringBuilder` and invoke the `append` method to
handle it.
the bytecode is as follows:
` L0
LINENUMBER 6 L0
LDC "abc"
ASTORE 1
L1
LINENUMBER 7 L1
NEW java/lang/StringBuilder
DUP
INVOKESPECIAL java/lang/StringBuilder.<init> ()V
ALOAD 1
INVOKEVIRTUAL java/lang/StringBuilder.append
(Ljava/lang/String;)Ljava/lang/StringBuilder;
LDC "d"
INVOKEVIRTUAL java/lang/StringBuilder.append
(Ljava/lang/String;)Ljava/lang/StringBuilder;
INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String;
ASTORE 1
L2
LINENUMBER 10 L2
GETSTATIC java/lang/System.out : Ljava/io/PrintStream;
ALOAD 1
INVOKEVIRTUAL java/io/PrintStream.println (Ljava/lang/String;)V
L3
LINENUMBER 11 L3
RETURN
L4
LOCALVARIABLE args [Ljava/lang/String; L0 L4 0
LOCALVARIABLE a Ljava/lang/String; L1 L4 1
MAXSTACK = 2
MAXLOCALS = 2`
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