Add some guidance for running Java debugger

This finishes wiring up the TEST_JAVA_ARGS CMake variable to allow
builders to override the JVM flags during unit test runs. We can then
use that to instantiate a remote debug server as a workaround for
debugging ACCP.

Author: geedo0

DEVELOPMENT-GUIDE.md

@@ -191,4 +191,27 @@ So, when you are in a critical region there are exceedingly few operations you c
 Essentially, all you can do is methods which manipulate your critical region until you get out of it.
 It is **extremely important** that you do not allocate *any* Java memory (such as creating Java objects, like a Java Exception), call *any* Java methods (which you shouldn't be doing anyway), or take any actions which may block.
 It is also **very important** that you don't spend too much time (more than about a millisecond) in a critical region.
-If you are concerned that an operation is not reasonably time-bounded, you should probably be sure to release the critical region on a regular basis to ensure the JVM has the opportunity to do needed memory management. (This isn't always achievable when everything is happening within a single atomic cryptographic operation.)
+If you are concerned that an operation is not reasonably time-bounded, you should probably be sure to release the critical region on a regular basis to ensure the JVM has the opportunity to do needed memory management. (This isn't always achievable when everything is happening within a single atomic cryptographic operation.)
+
+# Java Debugger Support
+Due to ACCP's unconventional build system, IDEs are not able to automatically configure, run, and debug the unit tests.
+This is largely because of how we use of Gradle/CMake to run the unit tests via the JUnit CLI which allows us to
+incorporate the natively compiled portion of the library. A simple workaround is to use the singleTest task along with
+JVM arguments to start a remote Java debugger session. This then allows you to connect and debug your test in the IDE.
+
+```
+# 1. Create a new Run/Debug Configuration for "Remote JVM Debug" in IntelliJ or the equivalent for your IDE.
+
+# 2. Launch your test target using the singlelTest target. n.b. Suspend is set to y to break immediately.
+TEST_CLASS=com.amazon.corretto.crypto.provider.test.KeyGeneratorTest
+./gradlew \
+-DTEST_JAVA_ARGS='-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:5005' \
+-DSINGLE_TEST=${TEST_CLASS} \
+singleTest
+
+# 3. Wait for the server to start listening.
+...
+Listening for transport dt_socket at address: 5005
+
+# 4. Set a breakpoint in the IDE and connect to the JVM debug server.
+```

build.gradle

@@ -341,29 +341,27 @@ task executeCmake(type: Exec) {
     if (isExperimentalFips) {
         args '-DEXPERIMENTAL_FIPS=ON'
     }
-
     if (prebuiltJar != null) {
        args '-DSIGNED_JAR=' + prebuiltJar
        println "Using SIGNED_JAR=${prebuiltJar}"
     }
-
     if (System.properties['JAVA_HOME'] != null) {
         args '-DJAVA_HOME=' + System.properties['JAVA_HOME']
     }
-
     if (System.properties['TEST_JAVA_HOME'] != null) {
         args '-DTEST_JAVA_HOME=' + System.properties['TEST_JAVA_HOME']
     }
     if (System.properties['TEST_JAVA_MAJOR_VERSION'] != null) {
         args '-DTEST_JAVA_MAJOR_VERSION=' + System.properties['TEST_JAVA_MAJOR_VERSION']
     }
+    if (System.properties['TEST_JAVA_ARGS'] != null) {
+        args '-DTEST_JAVA_ARGS=' + System.properties['TEST_JAVA_ARGS']
+    }
     if (System.properties['SINGLE_TEST'] != null) {
         args '-DSINGLE_TEST=' + System.properties['SINGLE_TEST']
-
     }
     if (System.properties['USE_CLANG_TIDY'] != null) {
         args '-DUSE_CLANG_TIDY=' + System.properties['USE_CLANG_TIDY']
-
     }
     args projectDir
 }