Fix comment on how java rules handle unknown output files

Test: none
Change-Id: I985e7961c87dd145d6eb2bd94cb8bdc43becc360

java/builder.go

@@ -35,9 +35,9 @@ var (
 	// Compiling java is not conducive to proper dependency tracking.  The path-matches-class-name
 	// requirement leads to unpredictable generated source file names, and a single .java file
 	// will get compiled into multiple .class files if it contains inner classes.  To work around
-	// this, all java rules write into separate directories and then a post-processing step lists
-	// the files in the the directory into a list file that later rules depend on (and sometimes
-	// read from directly using @<listfile>)
+	// this, all java rules write into separate directories and then are combined into a .jar file
+	// (if the rule produces .class files) or a .srcjar file (if the rule produces .java files).
+	// .srcjar files are unzipped into a temporary directory when compiled with javac.
 	javac = pctx.AndroidGomaStaticRule("javac",
 		blueprint.RuleParams{
 			Command: `rm -rf "$outDir" "$annoDir" "$srcJarDir" && mkdir -p "$outDir" "$annoDir" "$srcJarDir" && ` +