[JAVA] Try using another Servlet container Jetty with Docker

Eclipse Jetty is a Java Servlet execution environment (servant container, partial implementation of Java EE) and a web server. Apache Tomcat is a well-known implementation of the Servlet container, but Jetty is older [^ 1] and lighter [^ 2]. Commercial support is provided by the active contributor Webtide and embedded in Apache Hadoop. / Jetty) or used by Google App Engine.

[^ 1]: Jetty was first released in 1995 and Tomcat was first released in 1999.

Jetty has a smaller memory footprint than Tomcat, which helps save resources when running Java Servlets in a containerized virtualized environment. This article introduces the procedure for using Jetty on Docker.

Use Jetty with Docker

Docker Official Image is provided [^ 3]. You can choose an image from a combination of OpenJDK LTS (Red Hat build) and JRE, Debian and Debian slim for each version of Jetty.

Here we select Jetty9 on OpenJDK11 on Debian10:

[^ 3]: By the way, Google Cloud Platform Jetty Docker Image is also published under Apache-2.0 license.

docker pull jetty:9.4.31-jdk11

Deploying the Servlet is easy, just put the WAR file in / var / lib / jetty / webapps, or the uncompressed Servlet directory:

FROM jetty:9.4.31-jdk11
ADD sample.war /var/lib/jetty/webapps

You can also specify any location in context.xml:

FROM jetty:9.4.31-jdk11
ADD sampleApp.xml /var/lib/jetty/webapps
ADD sample /usr/local/sample

sampleApp.xml

<Configure class="org.eclipse.jetty.webapp.WebAppContext">
    <Set name="contextPath">/sample</Set>
    <Set name="war">/usr/local/sample</Set>
</Configure>

Environmental setting

You can refer to the current preferences by specifying the --list-config option:

$ docker run --rm jetty:9.4.31-jdk11 --list-config

Java Environment:
-----------------
 java.home = /usr/local/openjdk-11 (null)
 java.vm.vendor = Oracle Corporation (null)
 java.vm.version = 11.0.8+10 (null)
 java.vm.name = OpenJDK 64-Bit Server VM (null)
 java.vm.info = mixed mode (null)
 java.runtime.name = OpenJDK Runtime Environment (null)
 java.runtime.version = 11.0.8+10 (null)
 java.io.tmpdir = /tmp/jetty (null)
 user.dir = /var/lib/jetty (null)
 user.language = en (null)
 user.country = null (null)

Jetty Environment:
-----------------
 jetty.version = 9.4.31.v20200723
 jetty.tag.version = master
 jetty.home = /usr/local/jetty
 jetty.base = /var/lib/jetty

Config Search Order:
--------------------
 <command-line>
 ${jetty.base} -> /var/lib/jetty
 ${jetty.home} -> /usr/local/jetty


JVM Arguments:
--------------
 (no jvm args specified)

System Properties:
------------------
 (no system properties specified)

Properties:
-----------
 java.version = 11.0.8
 java.version.major = 11
 java.version.micro = 8
 java.version.minor = 0
 java.version.platform = 11
 jetty.base = /var/lib/jetty
 jetty.base.uri = file:///var/lib/jetty
 jetty.home = /usr/local/jetty
 jetty.home.uri = file:///usr/local/jetty

Jetty Server Classpath:
-----------------------
Version Information on 37 entries in the classpath.
Note: order presented here is how they would appear on the classpath.
      changes to the --module=name command line options will be reflected here.
 0:      1.4.1.v201005082020 | ${jetty.home}/lib/mail/javax.mail.glassfish-1.4.1.v201005082020.jar
 1:                    (dir) | ${jetty.base}/resources
 2:                    3.1.0 | ${jetty.home}/lib/servlet-api-3.1.jar
 3:                 3.1.0.M0 | ${jetty.home}/lib/jetty-schemas-3.1.jar
 4:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-http-9.4.31.v20200723.jar
 5:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-server-9.4.31.v20200723.jar
 6:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-xml-9.4.31.v20200723.jar
 7:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-util-9.4.31.v20200723.jar
 8:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-io-9.4.31.v20200723.jar
 9:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-jndi-9.4.31.v20200723.jar
10:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-security-9.4.31.v20200723.jar
11:                      1.3 | ${jetty.home}/lib/transactions/javax.transaction-api-1.3.jar
12:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-servlet-9.4.31.v20200723.jar
13:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-webapp-9.4.31.v20200723.jar
14:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-plus-9.4.31.v20200723.jar
15:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-annotations-9.4.31.v20200723.jar
16:                    7.3.1 | ${jetty.home}/lib/annotations/asm-7.3.1.jar
17:                    7.3.1 | ${jetty.home}/lib/annotations/asm-analysis-7.3.1.jar
18:                    7.3.1 | ${jetty.home}/lib/annotations/asm-commons-7.3.1.jar
19:                    7.3.1 | ${jetty.home}/lib/annotations/asm-tree-7.3.1.jar
20:                      1.3 | ${jetty.home}/lib/annotations/javax.annotation-api-1.3.jar
21:    3.19.0.v20190903-0936 | ${jetty.home}/lib/apache-jsp/org.eclipse.jdt.ecj-3.19.0.jar
22:         9.4.31.v20200723 | ${jetty.home}/lib/apache-jsp/org.eclipse.jetty.apache-jsp-9.4.31.v20200723.jar
23:                   8.5.54 | ${jetty.home}/lib/apache-jsp/org.mortbay.jasper.apache-el-8.5.54.jar
24:                   8.5.54 | ${jetty.home}/lib/apache-jsp/org.mortbay.jasper.apache-jsp-8.5.54.jar
25:                    1.2.5 | ${jetty.home}/lib/apache-jstl/org.apache.taglibs.taglibs-standard-impl-1.2.5.jar
26:                    1.2.5 | ${jetty.home}/lib/apache-jstl/org.apache.taglibs.taglibs-standard-spec-1.2.5.jar
27:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-client-9.4.31.v20200723.jar
28:         9.4.31.v20200723 | ${jetty.home}/lib/jetty-deploy-9.4.31.v20200723.jar
29:                      1.0 | ${jetty.home}/lib/websocket/javax.websocket-api-1.0.jar
30:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/javax-websocket-client-impl-9.4.31.v20200723.jar
31:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/javax-websocket-server-impl-9.4.31.v20200723.jar
32:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/websocket-api-9.4.31.v20200723.jar
33:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/websocket-client-9.4.31.v20200723.jar
34:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/websocket-common-9.4.31.v20200723.jar
35:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/websocket-server-9.4.31.v20200723.jar
36:         9.4.31.v20200723 | ${jetty.home}/lib/websocket/websocket-servlet-9.4.31.v20200723.jar

Jetty Active XMLs:
------------------
 ${jetty.home}/etc/jetty-bytebufferpool.xml
 ${jetty.home}/etc/jetty-threadpool.xml
 ${jetty.home}/etc/jetty.xml
 ${jetty.home}/etc/jetty-webapp.xml
 ${jetty.home}/etc/jetty-plus.xml
 ${jetty.home}/etc/jetty-annotations.xml
 ${jetty.home}/etc/jetty-deploy.xml
 ${jetty.home}/etc/jetty-http.xml

Please refer to Official Documentation for the items that can be set.

The JVM options can be specified with the environment variable JAVA_OPTIONS.

Reference link

• Eclipse Jetty
• What Version Do I Use?
• Adopt Jetty for Google App Engine