Make the default config sources more robust when a security manager is installed (#8544)

* Make the default config sources more robust when a security manager is installed
  If we don't have permission to access system properties or the environment then fall back to defaults.
* Exclude from instruction coverage as hard to test security exception case in this module

Author: mcculls

internal-api/build.gradle

@@ -221,7 +221,11 @@ excludedClassesBranchCoverage = [
   'datadog.trace.util.stacktrace.HotSpotStackWalker',
   'datadog.trace.util.stacktrace.StackWalkerFactory'
 ]
-excludedClassesInstructionCoverage = ['datadog.trace.util.stacktrace.StackWalkerFactory']
+excludedClassesInstructionCoverage = [
+  'datadog.trace.bootstrap.config.provider.EnvironmentConfigSource',
+  'datadog.trace.bootstrap.config.provider.SystemPropertiesConfigSource',
+  'datadog.trace.util.stacktrace.StackWalkerFactory'
+]
 
 compileTestJava.dependsOn 'generateTestClassNameTries'
 

internal-api/src/main/java/datadog/trace/bootstrap/config/provider/EnvironmentConfigSource.java

@@ -8,7 +8,11 @@ final class EnvironmentConfigSource extends ConfigProvider.Source {
 
   @Override
   protected String get(String key) {
-    return System.getenv(propertyNameToEnvironmentVariableName(key));
+    try {
+      return System.getenv(propertyNameToEnvironmentVariableName(key));
+    } catch (SecurityException e) {
+      return null;
+    }
   }
 
   @Override

internal-api/src/main/java/datadog/trace/bootstrap/config/provider/SystemPropertiesConfigSource.java

@@ -8,7 +8,11 @@ public final class SystemPropertiesConfigSource extends ConfigProvider.Source {
 
   @Override
   protected String get(String key) {
-    return System.getProperty(propertyNameToSystemPropertyName(key));
+    try {
+      return System.getProperty(propertyNameToSystemPropertyName(key));
+    } catch (SecurityException e) {
+      return null;
+    }
   }
 
   @Override