Code (Pre-)Review for JEP 280: Indify String Concat

[Andrej Golovnin]

Hi Aleksey,

>   http://cr.openjdk.java.net/~shade/8085796/webrev.langtools.02/

test/tools/javac/T5024091/T5024091.java
src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/StringConcat.java

The files do not have the copyright header.

And I have one stupid question to com.sun.tools.javac.jvm.StringConcat:

The constants TAG_ARG and TAG_CONST are defined as Strings. From
performance standpoint of view, would it be not better to use char
instead of String?

I understand that:

if (a.contains(TAG_CONST) || a.contains(TAG_ARG))

is easier to read than:

if (a.indexOf(TAG_CONST) != -1 || a.indexOf(TAG_ARG) != -1)

But when you have a huge project to compile, maybe it can help to
reduce the compile time.


The line 330 in com.sun.tools.javac.jvm.StringConcat:

330                 recipe.append("null");

Maybe it is better to rewrite it as:

330                 recipe.append((String) null);

The first one requires to copy byte values from the "null" String. The
second one ends up in the call to AsbtractStringBuilder.appendNull().

Best regards,
Andrej Golovnin