Derby Hat

Building Derby

About This Document

These are the instructions for building the Derby jar files from the Derby sources.


Before building Derby, you need to download the following:

Prerequisite Description
Derby Source If you are reading these instructions, chances are you have already unpacked a Derby source distribution. However, if you don't have the Derby source yet, get the development source tree from subversion by following these instructions.
Java Development Kit You need to install a Java 8 JDK. Probably, your machine already has this JDK. If not, Oracle and IBM supply free JDKs for many machines.
Ant You need to install the Ant build tool, version 1.9.2 or higher. You can get Ant here.

If you are going to run the Derby tests, then you will need to download the JUnit test harness also:

Prerequisite Description
JUnit You need the JUnit test tool, version 3.8.2. The Ant build script will try to download JUnit for you automatically if it's missing. If this fails for some reason, you can download and install JUnit manually. You can get JUnit 3.8.2 here. Copy junit.jar into your Derby source tree, in the tools/java directory.

Simple Build

Before building Derby, cd to the root of your Derby source distribution. That is the top level directory which contains the LICENSE and NOTICE files. In addition, make sure that the version of Java which you are using is Java 8. You can verify this by checking the output of the following command:

java -version

Now use the following Ant targets to build Derby.:

Target Description Command
clobber This target deletes all build artifacts.

ant -quiet clobber
buildsource This target compiles all source files needed for the Derby product. Don't be alarmed by all of the compiler warnings. We'll show you how to tidy those up later on.

ant -quiet buildsource
buildjars This target builds the Derby jar files.

ant -quiet buildjars

So, do this:

ant -quiet clobber
ant -quiet buildsource
ant -quiet buildjars

In order to build the Derby javadoc, you will need to run another target:

Target Description Command
javadoc This target builds the Derby javadoc. Be patient. The javadoc target takes a while.

ant -quiet javadoc

Verifying the Build

Run the sysinfo command to verify that the jars built correctly. This program will print out the Derby build information:

java -jar jars/sane/derbyrun.jar sysinfo

Testing Derby

If you want to build and run the Derby tests, make sure that you have downloaded the JUnit test framework. Then build all of the Derby sources, including the test classes:

Target Description Command
all This target compiles all Derby source files.

ant -quiet all

Putting all of this together, here's how you build the tests:

ant -quiet clobber
ant -quiet all
ant -quiet buildjars

To run the tests, consult the testing README.

Customized Build

You can customize the Derby build by setting variables in a file called The Ant tool looks for this file in your home directory. To find out where Ant thinks your home directory is, issue the following command and look for "user.home" in the output:

ant -diagnostics

Alternatively, or additionally, you can place properties in a file called '' in the top of the source tree. Properties placed in this file have precedence over those in user.home/

Here are some Derby-specific variables which you may want to set in

Variable Description Default Example
deprecation Turn this flag off if you don't want to see pages of warnings generated when the compiler encounters references to deprecated methods.

sane By default, this variable is set to true. This builds extra assertion and debugging logic into Derby classes. If you set this variable to false, then the Derby jar files will be smaller and Derby will run faster. During typical development, you will leave this variable set to true. However, this variable is set to false when building official Derby releases.

junit Setting this property will overwrite the default location for junit.jar, used to build the tests. The default location is tools/java. If you set this property, the build will not automatically download junit.jar, and if it's not in the specified location, the build will stop.


Advanced Build

Derby is supposed to run in the following environment:

Platform JDBC Level
Java 8 JDBC 4.2

The default Derby build does NOT necessarily verify that the compile-time contract is satisfied for this platform. To get compile-time checks, you need to make sure that the following variable is set correctly. To see the value which the Derby build uses for this variable, build Derby after setting the following debug variable in your


Here is the variable which determines whether the Derby build enforces compile-time contracts for the supported platform:

Platform Compiler Variable Description Default Value
Java 8 java18compile.classpath The set of libraries in the Java 8 JDK. The build fails if your environment isn't a Java 8 JDK. The set of system jars in your JDK if your environment is JDK 8. Otherwise, the build fails.

The preceding variable is mandatory for the Derby build. You can also force the setting of the preceding variable by setting the following optional library variable in

Compiler Variable Description Default Value
j18lib If you set this variable to be the directory which contains your Java 8 jars, then the Derby build will set java18compile.classpath to be the list of jars in that directory. Optional variable. No default value.

Here, for instance, are some sample settings of classpath variables (you should omit the \ continuation markers, which are included in these examples simply to improve readability):

java18compile.classpath =
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/charsets.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/deploy.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/htmlconverter.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/javaws.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jce.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jfr.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jfxswt.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jsse.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/management-agent.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/plugin.jar: \
    /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/resources.jar: \