| = Support for Java 11 |
| |
| In the new Java release cadence a new Java version is made available |
| every six months. The more frequent release cycle is favored as it |
| brings new Java features to the developers as and when they are |
| developed without the wait that the earlier 3 year release model |
| incurred. Not every Java version is a Long Term Support (LTS) version. |
| After Java 8 the next LTS version is Java 11. Java 9, 10, 12 and 13 are |
| all non-LTS versions. |
| |
| One of the objectives of the Apache Cassandra 4.0 version is to support |
| the recent LTS Java versions 8 and 11 |
| (https://issues.apache.org/jira/browse/CASSANDRA-9608[CASSANDRA-9608]). |
| Java 8 and Java 11 may be used to build and run Apache Cassandra 4.0. Effective Cassandra |
| 4.0.2 there is full Java 11 support, it is not experimental anymore. |
| |
| == Support Matrix |
| |
| The support matrix for the Java versions for compiling and running |
| Apache Cassandra 4.0 is detailed in Table 1. The build version is along |
| the vertical axis and the run version is along the horizontal axis. |
| |
| Table 1 : Support Matrix for Java |
| |
| [width="68%",cols="34%,30%,36%",] |
| |=== |
| | |Java 8 (Run) |Java 11 (Run) |
| |Java 8 (Build) |Supported |Supported |
| |Java 11(Build) |Not Supported |Supported |
| |=== |
| |
| Essentially Apache 4.0 source code built with Java 11 cannot be run with |
| Java 8. Next, we shall discuss using each of Java 8 and 11 to build and |
| run Apache Cassandra 4.0. |
| |
| == Using Java 8 to Build |
| |
| To start with, install Java 8. As an example, for installing Java 8 on |
| RedHat Linux the command is as follows: |
| |
| .... |
| $ sudo yum install java-1.8.0-openjdk-devel |
| .... |
| |
| Set `JAVA_HOME` and `JRE_HOME` environment variables in the shell bash |
| script. First, open the bash script: |
| |
| .... |
| $ sudo vi ~/.bashrc |
| .... |
| |
| Set the environment variables including the `PATH`. |
| |
| .... |
| $ export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk |
| $ export JRE_HOME=/usr/lib/jvm/java-1.8.0-openjdk/jre |
| $ export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin |
| .... |
| |
| Download and install Apache Cassandra 4.0 source code from the Git along |
| with the dependencies. |
| |
| .... |
| $ git clone https://github.com/apache/cassandra.git |
| .... |
| |
| If Cassandra is already running stop Cassandra with the following |
| command. |
| |
| .... |
| [ec2-user@ip-172-30-3-146 bin]$ ./nodetool stopdaemon |
| .... |
| |
| Build the source code from the `cassandra` directory, which has the |
| `build.xml` build script. The Apache Ant uses the Java version set in |
| the `JAVA_HOME` environment variable. |
| |
| .... |
| $ cd ~/cassandra |
| $ ant |
| .... |
| |
| Apache Cassandra 4.0 gets built with Java 8. Set the environment |
| variable for `CASSANDRA_HOME` in the bash script. Also add the |
| `CASSANDRA_HOME/bin` to the `PATH` variable. |
| |
| .... |
| $ export CASSANDRA_HOME=~/cassandra |
| $ export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin:$CASSANDRA_HOME/bin |
| .... |
| |
| To run Apache Cassandra 4.0 with either of Java 8 or Java 11 run the |
| Cassandra application in the `CASSANDRA_HOME/bin` directory, which is in |
| the `PATH` env variable. |
| |
| .... |
| $ cassandra |
| .... |
| |
| The Java version used to run Cassandra gets output as Cassandra is |
| getting started. As an example if Java 11 is used, the run output should |
| include similar to the following output snippet: |
| |
| .... |
| INFO [main] 2019-07-31 21:18:16,862 CassandraDaemon.java:480 - Hostname: ip-172-30-3- |
| 146.ec2.internal:7000:7001 |
| INFO [main] 2019-07-31 21:18:16,862 CassandraDaemon.java:487 - JVM vendor/version: OpenJDK |
| 64-Bit Server VM/11.0.3 |
| INFO [main] 2019-07-31 21:18:16,863 CassandraDaemon.java:488 - Heap size: |
| 1004.000MiB/1004.000MiB |
| .... |
| |
| The following output indicates a single node Cassandra 4.0 cluster has |
| started. |
| |
| .... |
| INFO [main] 2019-07-31 21:18:19,687 InboundConnectionInitiator.java:130 - Listening on |
| address: (127.0.0.1:7000), nic: lo, encryption: enabled (openssl) |
| ... |
| ... |
| INFO [main] 2019-07-31 21:18:19,850 StorageService.java:512 - Unable to gossip with any |
| peers but continuing anyway since node is in its own seed list |
| INFO [main] 2019-07-31 21:18:19,864 StorageService.java:695 - Loading persisted ring state |
| INFO [main] 2019-07-31 21:18:19,865 StorageService.java:814 - Starting up server gossip |
| INFO [main] 2019-07-31 21:18:20,088 BufferPool.java:216 - Global buffer pool is enabled, |
| when pool is exhausted (max is 251.000MiB) it will allocate on heap |
| INFO [main] 2019-07-31 21:18:20,110 StorageService.java:875 - This node will not auto |
| bootstrap because it is configured to be a seed node. |
| ... |
| ... |
| INFO [main] 2019-07-31 21:18:20,809 StorageService.java:1507 - JOINING: Finish joining ring |
| INFO [main] 2019-07-31 21:18:20,921 StorageService.java:2508 - Node 127.0.0.1:7000 state |
| jump to NORMAL |
| .... |
| |
| == Using Java 11 to Build |
| |
| If Java 11 is used to build Apache Cassandra 4.0, first Java 11 must be |
| installed and the environment variables set. As an example, to download |
| and install Java 11 on RedHat Linux run the following command. |
| |
| .... |
| $ yum install java-11-openjdk-devel |
| .... |
| |
| Set the environment variables in the bash script for Java 11. The first |
| command is to open the bash script. |
| |
| .... |
| $ sudo vi ~/.bashrc |
| $ export JAVA_HOME=/usr/lib/jvm/java-11-openjdk |
| $ export JRE_HOME=/usr/lib/jvm/java-11-openjdk/jre |
| $ export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin |
| .... |
| |
| To build source code with Java 11 one of the following two options must |
| be used. |
| |
| ____ |
| [arabic] |
| . {blank} |
| + |
| Include Apache Ant command-line option `-Duse.jdk=11` as follows::: |
| .... |
| $ ant -Duse.jdk=11 |
| .... |
| . {blank} |
| + |
| Set environment variable `CASSANDRA_USE_JDK11` to `true`::: |
| .... |
| $ export CASSANDRA_USE_JDK11=true |
| .... |
| ____ |
| |
| As an example, set the environment variable `CASSANDRA_USE_JDK11` to |
| `true`. |
| |
| .... |
| [ec2-user@ip-172-30-3-146 cassandra]$ export CASSANDRA_USE_JDK11=true |
| [ec2-user@ip-172-30-3-146 cassandra]$ ant |
| Buildfile: /home/ec2-user/cassandra/build.xml |
| .... |
| |
| Or, set the command-line option. |
| |
| .... |
| [ec2-user@ip-172-30-3-146 cassandra]$ ant -Duse.jdk11=true |
| .... |
| |
| The build output should include the following. |
| |
| .... |
| _build_java: |
| [echo] Compiling for Java 11 |
| ... |
| ... |
| build: |
| |
| _main-jar: |
| [copy] Copying 1 file to /home/ec2-user/cassandra/build/classes/main/META-INF |
| [jar] Building jar: /home/ec2-user/cassandra/build/apache-cassandra-4.0-SNAPSHOT.jar |
| ... |
| ... |
| _build-test: |
| [javac] Compiling 739 source files to /home/ec2-user/cassandra/build/test/classes |
| [copy] Copying 25 files to /home/ec2-user/cassandra/build/test/classes |
| ... |
| ... |
| jar: |
| [mkdir] Created dir: /home/ec2-user/cassandra/build/classes/stress/META-INF |
| [mkdir] Created dir: /home/ec2-user/cassandra/build/tools/lib |
| [jar] Building jar: /home/ec2-user/cassandra/build/tools/lib/stress.jar |
| [mkdir] Created dir: /home/ec2-user/cassandra/build/classes/fqltool/META-INF |
| [jar] Building jar: /home/ec2-user/cassandra/build/tools/lib/fqltool.jar |
| |
| BUILD SUCCESSFUL |
| Total time: 1 minute 3 seconds |
| [ec2-user@ip-172-30-3-146 cassandra]$ |
| .... |
| |
| == Common Issues |
| |
| One of the two options mentioned must be used to compile with JDK 11 or |
| the build fails and the following error message is output. |
| |
| .... |
| [ec2-user@ip-172-30-3-146 cassandra]$ ant |
| Buildfile: /home/ec2-user/cassandra/build.xml |
| validate-build-conf: |
| |
| BUILD FAILED |
| /home/ec2-user/cassandra/build.xml:293: -Duse.jdk11=true or $CASSANDRA_USE_JDK11=true must |
| be set when building from java 11 |
| Total time: 1 second |
| [ec2-user@ip-172-30-3-146 cassandra]$ |
| .... |
| |
| The Java 11 built Apache Cassandra 4.0 source code may be run with Java |
| 11 only. If a Java 11 built code is run with Java 8 the following error |
| message gets output. |
| |
| .... |
| [root@localhost ~]# ssh -i cassandra.pem ec2-user@ec2-3-85-85-75.compute-1.amazonaws.com |
| Last login: Wed Jul 31 20:47:26 2019 from 75.155.255.51 |
| [ec2-user@ip-172-30-3-146 ~]$ echo $JAVA_HOME |
| /usr/lib/jvm/java-1.8.0-openjdk |
| [ec2-user@ip-172-30-3-146 ~]$ cassandra |
| ... |
| ... |
| Error: A JNI error has occurred, please check your installation and try again |
| Exception in thread "main" java.lang.UnsupportedClassVersionError: |
| org/apache/cassandra/service/CassandraDaemon has been compiled by a more recent version of |
| the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes |
| class file versions up to 52.0 |
| at java.lang.ClassLoader.defineClass1(Native Method) |
| at java.lang.ClassLoader.defineClass(ClassLoader.java:763) |
| at ... |
| ... |
| .... |
| |
| The `CASSANDRA_USE_JDK11` variable or the command-line option |
| `-Duse.jdk11` cannot be used to build with Java 8. To demonstrate set |
| `JAVA_HOME` to version 8. |
| |
| .... |
| [root@localhost ~]# ssh -i cassandra.pem ec2-user@ec2-3-85-85-75.compute-1.amazonaws.com |
| Last login: Wed Jul 31 21:41:50 2019 from 75.155.255.51 |
| [ec2-user@ip-172-30-3-146 ~]$ echo $JAVA_HOME |
| /usr/lib/jvm/java-1.8.0-openjdk |
| .... |
| |
| Set the `CASSANDRA_USE_JDK11=true` or command-line option |
| `-Duse.jdk11=true`. Subsequently, run Apache Ant to start the build. The |
| build fails with error message listed. |
| |
| .... |
| [ec2-user@ip-172-30-3-146 ~]$ cd |
| cassandra |
| [ec2-user@ip-172-30-3-146 cassandra]$ export CASSANDRA_USE_JDK11=true |
| [ec2-user@ip-172-30-3-146 cassandra]$ ant |
| Buildfile: /home/ec2-user/cassandra/build.xml |
| |
| validate-build-conf: |
| |
| BUILD FAILED |
| /home/ec2-user/cassandra/build.xml:285: -Duse.jdk11=true or $CASSANDRA_USE_JDK11=true cannot |
| be set when building from java 8 |
| |
| Total time: 0 seconds |
| .... |
