Hi All, I have fixed some warnings in java.base module, following are 3 type of code changes in this patch: ! stream().filter(...).findFirst().isPresent() replaced with stream().noneMatch(...)) stream.filter(...).findFirst().isPresent() replaced with stream.anyMatch(...) stream.collect(Collectors.joining(",")) replaced with String.join(",", stringList) This patch improves performance as well, jmh results available at https://gist.github.com/Vipin-Sharma/00f1d6da6b8e0e0bc7bec2e33bce85ed, end of gist file you can see results. Need a sponsor for this patch. Patch: --- old/src/java.base/share/classes/java/lang/invoke/MethodHandles.java 2020-05-03 19:44:09.519289354 +0530 +++ new/src/java.base/share/classes/java/lang/invoke/MethodHandles.java 2020-05-03 19:44:09.087294954 +0530 @@ -6349,7 +6349,7 @@ loopReturnType + ")"); } - if (!pred.stream().filter(Objects::nonNull).findFirst().isPresent()) { + if (pred.stream().noneMatch(Objects::nonNull)) { throw newIllegalArgumentException("no predicate found", pred); } if (pred.stream().filter(Objects::nonNull).map(MethodHandle::type).map(MethodType::returnType). --- old/src/java.base/share/classes/java/util/Locale.java 2020-05-03 19:44:10.915271183 +0530 +++ new/src/java.base/share/classes/java/util/Locale.java 2020-05-03 19:44:10.487276766 +0530 @@ -1,5 +1,5 @@ /* - * Copyright (c) 1996, 2019, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1996, 2020, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -2250,7 +2250,7 @@ // If we have no list patterns, compose the list in a simple, // non-localized way. if (pattern == null) { - return Arrays.stream(stringList).collect(Collectors.joining(",")); + return String.join(",", stringList); } switch (stringList.length) { --- old/src/java.base/share/classes/jdk/internal/module/DefaultRoots.java 2020-05-03 19:44:11.911258115 +0530 +++ new/src/java.base/share/classes/jdk/internal/module/DefaultRoots.java 2020-05-03 19:44:11.479263786 +0530 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -74,8 +74,6 @@ private static boolean exportsAPI(ModuleDescriptor descriptor) { return descriptor.exports() .stream() - .filter(e -> !e.isQualified()) - .findAny() - .isPresent(); + .anyMatch(e -> !e.isQualified()); } } --- old/src/java.base/share/classes/sun/launcher/LauncherHelper.java 2020-05-03 19:44:12.863245549 +0530 +++ new/src/java.base/share/classes/sun/launcher/LauncherHelper.java 2020-05-03 19:44:12.427251308 +0530 @@ -1142,7 +1142,7 @@ ostream.format("uses %s%n", s); } for (Provides ps : md.provides()) { - String names = ps.providers().stream().collect(Collectors.joining(" ")); + String names = String.join(" ", ps.providers()); ostream.format("provides %s with %s%n", ps.service(), names); } @@ -1150,7 +1150,7 @@ // qualified exports for (Exports e : md.exports()) { if (e.isQualified()) { - String who = e.targets().stream().collect(Collectors.joining(" ")); + String who = String.join(" ", e.targets()); ostream.format("qualified exports %s to %s%n", e.source(), who); } } @@ -1164,7 +1164,7 @@ .collect(Collectors.joining(" ")); ostream.format("opens %s", sourceAndMods); if (opens.isQualified()) { - String who = opens.targets().stream().collect(Collectors.joining(" ")); + String who = String.join(" ", opens.targets()); ostream.format(" to %s", who); } ostream.println(); --- old/src/jdk.jshell/share/classes/jdk/internal/jshell/tool/JShellTool.java 2020-05-03 19:44:14.143228540 +0530 +++ new/src/jdk.jshell/share/classes/jdk/internal/jshell/tool/JShellTool.java 2020-05-03 19:44:13.711234292 +0530 @@ -380,7 +380,7 @@ return parse(oset); } catch (OptionException ex) { if (ex.options().isEmpty()) { - msg("jshell.err.opt.invalid", stream(args).collect(joining(", "))); + msg("jshell.err.opt.invalid", String.join(", ", args)); } else { boolean isKnown = parser.recognizedOptions().containsKey(ex.options().iterator().next()); msg(isKnown @@ -2041,16 +2041,14 @@ if (matches.length == 0) { // There are no matching sub-commands errormsg("jshell.err.arg", cmd, sub); - fluffmsg("jshell.msg.use.one.of", Arrays.stream(subs) - .collect(Collectors.joining(", ")) + fluffmsg("jshell.msg.use.one.of", String.join(", ", subs) ); return null; } if (matches.length > 1) { // More than one sub-command matches the initial characters provided errormsg("jshell.err.sub.ambiguous", cmd, sub); - fluffmsg("jshell.msg.use.one.of", Arrays.stream(matches) - .collect(Collectors.joining(", ")) + fluffmsg("jshell.msg.use.one.of", String.join(", ", matches) ); return null; } Regards, Vipin