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wolfSSL JNI and wolfJSSE Compilation

There are three ways to compile wolfJSSE listed in this chapter, including using the Unix Command Line, Android Studio Build and Generic IDE Build.

Unix Command Line

Before following steps in this section, please ensure that the dependencies listed in Chapter 2 are installed.

The script in the root package directory is used to compile the native JNI C source files into a shared library for either Unix/Linux or Mac OSX. This script tries to auto-detect between OSX (Darwin) and Linux to set up include paths and shared library extension type. This script directly calls gcc on the JNI C source files, producing ./lib/ or ./lib/libwolfssljni.jnilib.

$ ./

Compiling Native JNI library:
    WOLFSSL_INSTALL_DIR = /usr/local
    Detected Linux host OS
        Linux x86_64
    Java Home = /usr/lib/jvm/java-8-openjdk-amd64
    Generated ./lib/

If linking against a native wolfSSL library not installed to /usr/local, one argument may be passed to which represents the wolfSSL installation location. For example:

$ ./ /path/to/wolfssl/install

To compile the Java sources, ant is used:

$ ant

Available build targets for ant are :

  • ant (only builds the jar necessary for an app to use)
  • ant test (builds the jar and tests then runs the tests, requires JUNIT setup)
  • ant examples (builds the jar and example cases)
  • ant clean (cleans all Java artifacts)
  • ant cleanjni (cleans native artifacts)

These two commands will build the wolfJSSE jar and native code necessary to use wolfJSSE in a project. To compile and run JUnit tests the command ant test is used:

$ ant test

This will compile tests and the main wolfJSSE code and output with the results of the tests will be displayed along with a summary of total tests that passed at the end of the wolfJSSE testsuite and wolfSSL JNI testsuite. A successful build will display the message “BUILD SUCCESSFUL” at the end.

[junit] WolfSSLTrustX509 Class
[junit] Testing parse all_mixed.jks ... passed
[junit] Testing loading default certs ... passed
[junit] Testing parse all.jks ... passed
[junit] Testing verify ... passed


Total time: 18 seconds

To compile and run examples bundled with wolfJSSE the command ant examples is used:

$ ant examples

Android Studio Build

An example Android Studio project is located in the directory IDE/Android. This is an example Android Studio project file for wolfssljni / wolfJSSE. This project should be used for reference only.

More details on tool and version information used when testing can be found in the wolfssljni/IDE/Android/ The following steps outline what is required to run this example on an Android device or emulator.

1. Add Native wolfSSL Library Source Code to Project

This example project is already set up to compile and build the native wolfSSL library source files, but the wolfSSL files themselves have not been included in this package. You must download or link an appropriate version of wolfSSL to this project using one of the options below.

The project looks for the directory wolfssljni/IDE/Android/app/src/main/cpp/wolfssl for wolfSSL source code. This can added in multiple ways:

  • OPTION A: Download the latest wolfSSL library release from, unzip it, rename it to wolfssl, and place it in the direcotry wolfssljni/IDE/Android/app/src/main/cpp/.
$ unzip
$ mv wolfssl-X.X.X wolfssljni/IDE/Android/app/src/main/cpp/wolfssl
  • OPTION B: Alternatively GitHub can be used to clone wolfSSL:
$ cd /IDE/Android/app/src/main/cpp/
$ git clone
$ cp wolfssl/ wolfssl/options.h
  • OPTION C: A symbolic link to a wolfssl directory on the system by using:
$ cd /IDE/Android/app/src/main/cpp/
$ ln -s /path/to/local/wolfssl ./wolfssl

The following Java source directory is a Unix/Linux symlink:


This will not work correctly on Windows, and a new Windows symbolic link needs to be created in this location. To do so:

1) Open Windows Command Prompt (Right click, and "Run as Administrator") 2) Navigate to wolfssljni\IDE\Android\app\src\main\java\com 3) Delete the existing symlink file (it shows up as a file called "wolfssl")

del wolfssl

4) Create a new relative symbolic link with mklink:

mklink /D wolfssl ..\..\..\..\..\..\..\src\java\com\wolfssl\

3. Convert Example JKS files to BKS for Android Use

On an Android device BKS format key stores are expected. To convert the JKS example bundles to BKS use the following commands. Note: you will need to download a version of the bcprov JAR from the Bouncy Castle website:

cd examples/provider
./ <path/to/provider>

For exmaple, when using bcprov-ext-jdk15on-169.jar:

cd examples/provider
./ ~/Downloads/bcprov-ext-jdk15on-169.jar

4. Push BKS files to Android Device or Emulator

Push BKS bundles up to the device along with certificates. To do this start up the emulator/device and use adb push. An example of this would be the following commands from root wolfssljni directory. This step may be done after the starting Android Studio and compiling the project, but must be done before running the app or test cases.

adb shell
cd sdcard
mkdir examples
mkdir examples/provider
mkdir examples/certs
adb push ./examples/provider/*.bks /sdcard/examples/provider/
adb push ./examples/certs/ /sdcard/examples/
adb push ./examples/certs/intermediate/* /sdcard/examples/certs/intermediate/

5. Import and Build the Example Project with Android Studio

1) Open the Android Studio project by double clicking on the Android folder in wolfssljni/IDE/. Or, from inside Android Studio, open the Android project located in the wolfssljni/IDE directory.

2) Build the project and run MainActivity from app -> java/com/example.wolfssl. This will ask for permissions to access the certificates in the /sdcard/ directory and then print out the server certificate information on success.

3) OPTIONAL: The androidTests can be run after permissions has been given. app->java->com.wolfssl->provider.jsse.test->WolfSSLJSSETestSuite and app->java->com.wolfssl->test->WolfSSLTestSuite

Generic IDE Build

For generic IDE builds create a new project in the IDE, then add source files from src/java. This will be the following packages:


Run from the command line or have the IDE execute to generate the native shim layer linking against wolfSSL.

Add native library reference to the project. It should look in the lib directory for libwolfssl.jnilib (i.e. wolfssljni/lib/).

To compile test cases add the packages com.wolfssl.provider.jsse.test and com.wolfssl.test from the directory src/test. The project will also need Junit to run the tests.

If adding in optional examples then the source code in examples/provider/ can be added to the project. Optionally the IDE can execute examples/provider/ One of the difficult parts to adding in the examples is making sure the path to keystores is known to the IDE when it runs the examples, if trying to use the default keystores.