Plan API 5.2-R0.9: Fixed access issue with package private classes

Affects issues:
- Fixed #1862

Plan/api/build.gradle

@@ -4,7 +4,7 @@ dependencies {
     compileOnly "com.google.code.gson:gson:$gsonVersion"
 }
 
-ext.apiVersion = '5.2-R0.8'
+ext.apiVersion = '5.2-R0.9'
 
 publishing {
     repositories {

Plan/api/src/main/java/com/djrapitops/plan/extension/extractor/ExtensionExtractor.java

@@ -122,6 +122,13 @@ public final class ExtensionExtractor {
                 continue;
             }
 
+            try {
+                method.makeAccessible();
+            } catch (SecurityException failedToMakeAccessible) {
+                throw new IllegalArgumentException(extensionName + "." + method.getMethodName() + " could not be made accessible: " +
+                        failedToMakeAccessible.getMessage(), failedToMakeAccessible);
+            }
+
             method.getAnnotation(BooleanProvider.class).ifPresent(annotation -> {
                 validateMethod(method, annotation);
                 methods.get(method.getParameterType()).addBooleanMethod(method);

Plan/api/src/main/java/com/djrapitops/plan/extension/extractor/ExtensionMethod.java

@@ -77,6 +77,15 @@ public class ExtensionMethod {
         return getMethod().getName();
     }
 
+    /**
+     * @throws SecurityException If access modification fails.
+     */
+    public void makeAccessible() {
+        if (!method.isAccessible()) {
+            method.setAccessible(true);
+        }
+    }
+
     public enum ParameterType {
         SERVER_NONE(null),
         PLAYER_STRING(String.class),