Master Tomcat: Install, Configure, and Optimize Your Java Web Server

Tomcat Introduction

Tomcat is a free, open‑source web application server that serves as a lightweight servlet and JSP container, ideal for small‑to‑medium projects and for developing and debugging JSP programs. It runs as an independent process, often alongside Apache which handles static HTML.

Tomcat Installation

Prerequisites

Before installing Tomcat, install the Java Development Kit (JDK). The JDK provides the JVM, which executes compiled Java bytecode and ensures cross‑platform compatibility.

Download Links

JDK: http://www.oracle.com/technetwork/java/javase/downloads/

Tomcat: http://tomcat.apache.org

Installation Steps

# Remove existing OpenJDK
rm -rf $(which java)

# Extract JDK
tar xf jdk-7u80-linux-x64.tar

# Move JDK to /usr/local/java
mv jdk1.7.0_80/ /usr/local/java

# Extract Tomcat
tar xf apache-tomcat-8.5.20.tar.gz

# Move Tomcat to /usr/local/tomcat8
mv apache-tomcat-8.5.20 /usr/local/tomcat8

# Set JAVA environment variables
vim /etc/profile.d/java.sh
export JAVA_HOME="/usr/local/java"
export PATH=$PATH:$JAVA_HOME/bin:/usr/local/tomcat8/bin
. /etc/profile

# Verify Java version
java -version

# Start Tomcat
/usr/local/tomcat7/bin/startup.sh

# Stop Tomcat
/usr/local/tomcat7/bin/shutdown.sh

Port Modification

# Edit server.xml to change ports
vim /usr/local/tomcat8/conf/server.xml
# Example changes:
#   8080 -> 9528
#   8005 -> 9529
#   8009 -> 9530

Tomcat Optimization

Disable AJP Connector

# Comment out the AJP connector in server.xml
<!-- <Connector port="8009" protocol="AJP/1.3" redirectPort="8443"/> -->

Switch BIO to NIO

# Use NIO protocol for better concurrency
<Connector port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol"/>

Enable External Thread Pool

# Define an executor and reference it in the Connector
<Executor name="tomcatThreadPool" maxThreads="1000" minSpareThreads="100"/>
<Connector executor="tomcatThreadPool" port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol" maxThreads="1000" minSpareThreads="100" maxSpareThreads="200" acceptCount="1000" connectionTimeout="20000" URIEncoding="UTF-8" enableLookups="false" compression="on" compressionMinSize="2048" compressableMimeType="text/html,text/xml,text/javascript,text/css,text/plain,image/gif,image/jpg,image/png" redirectPort="8443"/>

JVM Tuning for Production

# Add to catalina.sh
JAVA_OPTS="-server -Xms1024m -Xmx2048m -XX:PermSize=512m -XX:MaxPermSize=512m -XX:+UseConcMarkSweepGC -XX:+UseParallelGCThreads=8 -XX:CMSInitiatingOccupancyFraction=80 -XX:+UseCMSCompactAtFullCollection -Xloggc:../logs/gc.log"

Tomcat Directory Layout

/usr/local/tomcat (installation directory)

bin – startup/shutdown scripts

conf – configuration files (server.xml, web.xml, etc.)

lib – required JAR libraries

logs – log files

webapps – deployed web applications

work – compiled JSP classes

After applying the above configurations, restart Tomcat to apply changes and verify that the server listens on the new ports.