[ https://issues.apache.org/jira/browse/HADOOP-15033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16297031#comment-16297031 ]
ASF GitHub Bot commented on HADOOP-15033: ----------------------------------------- Github user steveloughran commented on a diff in the pull request: https://github.com/apache/hadoop/pull/291#discussion_r157801677 --- Diff: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Shell.java --- @@ -89,6 +89,22 @@ public static boolean isJava7OrAbove() { return true; } + private static final boolean IS_JAVA9_OR_ABOVE; + static { + int major = 0; + try { + // 1.8.0 -> 1, 10-ea+30 -> 10, 18.03 -> 18, 11 -> 11 etc. + String version = System.getProperty("java.version"); + major = Integer.parseInt(version.split("\\.")[0].split("-")[0]); + } catch (NumberFormatException ignored) { + } + IS_JAVA9_OR_ABOVE = major >= 9; + } + + public static boolean isJava9OrAbove() { + return IS_JAVA9_OR_ABOVE; + } --- End diff -- Hadoop trunk is java 8+ only. * nobody will backport your patch to branch-2; its using Java 8 classes. * someone could backport an `isJavaVersionAtLeast()` method to branch-2, in which case, they get to extend it. > Use java.util.zip.CRC32C for Java 9 and above > --------------------------------------------- > > Key: HADOOP-15033 > URL: https://issues.apache.org/jira/browse/HADOOP-15033 > Project: Hadoop Common > Issue Type: Improvement > Components: performance, util > Affects Versions: 3.0.0 > Reporter: Dmitry Chuyko > Labels: Java9, common, jdk9 > Attachments: HADOOP-15033.001.patch, HADOOP-15033.001.patch, > HADOOP-15033.002.patch, HADOOP-15033.003.patch, HADOOP-15033.003.patch, > HADOOP-15033.004.patch > > > java.util.zip.CRC32C implementation is available since Java 9. > https://docs.oracle.com/javase/9/docs/api/java/util/zip/CRC32C.html > Platform specific assembler intrinsics make it more effective than any pure > Java implementation. > Hadoop is compiled against Java 8 but class constructor may be accessible > with method handle on 9 to instances implementing Checksum in runtime. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org