Hi Otávio, the class src/share/classes/com/sun/jmx/snmp/IPAcl/Parser.java is generated from the grammar
src/share/classes/com/sun/jmx/snmp/IPAcl/Parser.jjt src/share/classes/com/sun/jmx/snmp/IPAcl/Parser.jj Therefore when you are going to change the Parser class, then you must change the grammar files too. In other case your changes maybe overwritten in the future, when someone decides to regenerate the Parser class. The classes src/share/classes/com/sun/jmx/snmp/IPAcl/ParseException.java src/share/classes/com/sun/jmx/snmp/IPAcl/TokenMgrError.java are generated from the templates provided by JavaCC https://java.net/projects/javacc/sources/svn/show/trunk/src/main/resources/templates?rev=689 You should consider contributing you changes to the ParseException and TokenMgrError classes to the JavaCC project as well. In the class src/share/classes/javax/management/openmbean/CompositeType.java you have added the annotation @SuppressWarnings("StringConcatenationInsideStringBufferAppend") instead of fixing the concatenation inside the append method. Why? And I would like to suggest to drop explicit usage of StringBuilder in some methods at all to improve code readability. Take look for example at the class src/share/classes/java/lang/management/MemoryUsage.java and its #toString()-method: Before your change: 239 public String toString() { 240 StringBuilder buf = new StringBuilder(); 241 buf.append("init = " + init + "(" + (init >> 10) + "K) "); 242 buf.append("used = " + used + "(" + (used >> 10) + "K) "); 243 buf.append("committed = " + committed + "(" + 244 (committed >> 10) + "K) " ); 245 buf.append("max = " + max + "(" + (max >> 10) + "K)"); 246 return buf.toString(); 247 } After your change: 239 public String toString() { 240 StringBuilder buf = new StringBuilder(); 241 buf.append("init = ").append(init).append('(').append(init >> 10).append("K) "); 242 buf.append("used = ").append(used).append('(').append(used >> 10).append("K) "); 243 buf.append("committed = ").append(committed).append('(').append(committed >> 10).append("K) "); 244 buf.append("max = ").append(max).append('(').append(max >> 10).append("K)"); 245 return buf.toString(); 246 } And if we drop explicit usage of StringBuilder and let the Java compiler do its magic, then it looks like this: 239 public String toString() { 240 return "init = " + init + "(" + (init >> 10) + "K) " 241 + "used = " + used + "(" + (used >> 10) + "K) " 242 + "committed = " + committed + "(" + (committed >> 10) + "K) " 243 + "max = " + max + "(" + (max >> 10) + "K)"; 244 } For me this code is easier to read and understand, then the code before and after your change. But this is only my opinion. Other candidates for such change may be: src/share/classes/com/sun/crypto/provider/DHParameters.java src/share/classes/com/sun/crypto/provider/DHPublicKey.java src/share/classes/com/sun/crypto/provider/GCMParameters.java src/share/classes/com/sun/crypto/provider/OAEPParameters.java src/share/classes/com/sun/crypto/provider/RC2Parameters.java src/share/classes/java/security/CodeSigner.java src/share/classes/java/security/cert/CollectionCertStoreParameters.java src/share/classes/java/security/cert/LDAPCertStoreParameters.java src/share/classes/java/security/cert/PKIXBuilderParameters.java src/share/classes/java/security/cert/PKIXCertPathBuilderResult.java src/share/classes/java/security/cert/PKIXCertPathValidatorResult.java src/share/classes/java/security/cert/PolicyQualifierInfo.java src/share/classes/java/util/Scanner.java src/share/classes/java/util/regex/Matcher.java src/share/classes/javax/management/relation/RoleInfo.java src/share/classes/javax/naming/RefAddr.java src/share/classes/sun/security/pkcs/SigningCertificateInfo.java src/share/classes/sun/security/provider/certpath/CertId.java src/share/classes/sun/security/provider/certpath/SunCertPathBuilderParameters.java src/share/classes/sun/security/x509/DistributionPointName.java src/share/classes/sun/security/x509/PolicyInformation.java src/share/classes/sun/security/x509/X509CertImpl.java In the #toString()-method of src/share/classes/javax/swing/RepaintManager.java we can avoid creation of StringBuilder if we change it from: 992 public synchronized String toString() { 993 StringBuilder sb = new StringBuilder(); 994 if(dirtyComponents != null) 995 sb.append(dirtyComponents); 996 return sb.toString(); 997 } to: 992 public synchronized String toString() { 993 return dirtyComponents != null ? dirtyComponents.toString : ""; 994 } In src/share/classes/sun/net/www/HeaderParser.java please change the line 223 to use StringBuilder instead of StringBuffer. In the class src/share/classes/sun/security/ssl/ServerNameExtension.java the #toString()-method can be changed from: 268 public String toString() { 269 StringBuilder sb = new StringBuilder(); 270 for (SNIServerName sniName : sniMap.values()) { 271 sb.append('[').append(sniName).append(']'); 272 } 273 274 return "Extension " + type + ", server_name: " + sb; 275 } to: 268 public String toString() { 269 StringBuilder sb = new StringBuilder(); 270 sb.append("Extension ").append(type).append(", server_name: "); 271 for (SNIServerName sniName : sniMap.values()) { 272 sb.append('[').append(sniName).append(']'); 273 } 274 275 return sb.toString(); 276 } to avoid creation of an additional StringBuilder-object in the line 274. Similar change can be applied to the class src/share/classes/sun/security/ssl/SignatureAlgorithmsExtension.java. Best regards, Andrej Golovnin On Mon, Aug 11, 2014 at 5:29 AM, Otávio Gonçalves de Santana < otavioj...@java.net> wrote: > Done. > > > https://dl.dropboxusercontent.com/u/16109193/open_jdk/string_builder_concat_2.zip > > obs: stay the 2 chars to better performance. > > > On Sun, Aug 10, 2014 at 8:03 PM, Claes Redestad <claes.redes...@oracle.com > > > wrote: > > > +1 > > > > Some suggestions (mostly nits): > > > > - in places like src/share/classes/java/util/regex/Pattern.java you > > introducesingle-char > > strings which might use a char instead: > > > > - result.append("|"+next); > > + result.append('|').append(next); > > > > - in places like src/share/classes/sun/security/provider/PolicyFile.java > > you end up with a sequence of String literal appends which could be > > merged into one: > > > > - sb.append(principalInfo[i][0] + " " + > > - "\"" + principalInfo[i][1] + "\""); > > + sb.append(principalInfo[i][0]).append(" \"") > > + .append(principalInfo[i][1]).append('"'); > > > > - in some places like src/share/classes/java/text/ChoiceFormat.java > > you end up doing append(""). I guess the empty string concatenation was > > used as a form > > of primitive-to-string coercion and was probably always redundant > > already, but care needs > > to be taken that doing the append directly behave as intended. > > > > I think it should be safe to just remove the empty string append in > most > > cases: > > > > - result.append(""+choiceLimits[i]); > > + result.append(choiceLimits[i]); > > > > Thanks! > > > > /Claes > > > > On 2014-08-10 23:33, Otávio Gonçalves de Santana wrote: > > > >> *Motivation:* Make another append instead of concat String inside of > >> append > >> > >> parameter in StringBuilder class. To avoid an extra StringBuilder > created > >> for the purpose of concatenating. So it will save memory and will faster > >> than concat String. > >> Doing a code to benchMark[1], the result is: > >> > >> Benchmark Mode > Samples > >> Mean Mean error Units > >> m.StringBuilderConcatBenchMark.stringBuilder thrpt > 10 > >> 6317444.705 108673.584 ops/s > >> m.StringBuilderConcatBenchMark.stringBuilderWithConcat thrpt > 10 > >> 3354554.435 68353.924 ops/s > >> > >> The webrev of all code is: > >> https://dl.dropboxusercontent.com/u/16109193/open_jdk/ > >> string_builder_concat.zip > >> <https://dl.dropboxusercontent.com/u/16109193/open_jdk/string_ > >> builder_concat.zip> > >> > >> [1] > >> > >> @State(Scope.Thread) > >> @OutputTimeUnit(TimeUnit.SECONDS) > >> public class StringBuilderConcatBenchMark { > >> > >> > >> private static final String F = "!!!!"; > >> private static final String E = " running in Java "; > >> private static final String D = " in the code "; > >> private static final String C = " to try impact "; > >> private static final String B = " with some text "; > >> private static final String A = "Doing a test"; > >> > >> @GenerateMicroBenchmark > >> public void stringBuilder(BlackHole bh) { > >> bh.consume(createBuilder(A, B, C, D, E, F)); > >> } > >> > >> @GenerateMicroBenchmark > >> public void stringBuilderWithConcat(BlackHole bh) { > >> bh.consume(createBuilderWithConcat(A, B, C, D, E, F)); > >> } > >> > >> private StringBuilder createBuilder(String... values) { > >> StringBuilder text = new StringBuilder(); > >> text.append(values[0]).append(values[1]) > >> .append(values[2]).append(values[3]) > >> .append(values[4]).append(values[5]); > >> return text; > >> } > >> private StringBuilder createBuilderWithConcat(String... values) { > >> StringBuilder text = new StringBuilder(); > >> text.append(values[0] + values[1]) > >> .append(values[2] + values[3]) > >> .append(values[4]+ values[5]); > >> return text; > >> } > >> } > >> > >> > > > > > -- > Otávio Gonçalves de Santana > > blog: http://otaviosantana.blogspot.com.br/ > twitter: http://twitter.com/otaviojava > site: *http://about.me/otaviojava <http://about.me/otaviojava>* > 55 (11) 98255-3513 >
