Dev: fix enum encoding

Sources/JNICore+JavaCoder.swift

@@ -78,10 +78,12 @@ fileprivate extension NSLock {
     
 fileprivate var javaClasses = [String: jclass]()
 fileprivate var javaMethods = [String: jmethodID]()
+fileprivate var javaStaticMethods = [String: jmethodID]()
 fileprivate var javaFields = [String: jmethodID]()
 
 fileprivate let javaClassesLock = NSLock()
 fileprivate let javaMethodLock = NSLock()
+fileprivate let javaStaticMethodLock = NSLock()
 fileprivate let javaFieldLock = NSLock()
 
 public extension JNICore {
@@ -160,6 +162,26 @@ public extension JNICore {
         }
     }
     
+    public func getStaticJavaMethod(forClass className: String, method: String, sig: String) throws -> jmethodID {
+        let key = "\(className).\(method)\(sig)"
+        let javaClass = try getJavaClass(className)
+        if let methodID = javaStaticMethods[key] {
+            return methodID
+        }
+        return try javaStaticMethodLock.sync {
+            if let methodID = javaStaticMethods[key] {
+                return methodID
+            }
+            guard let javaMethodID = JNI.api.GetStaticMethodID(JNI.env, javaClass, method, sig) else {
+                JNI.api.ExceptionClear(JNI.env)
+                JNI.ExceptionReset()
+                throw JNIError.methodNotFoundException(key)
+            }
+            javaStaticMethods[key] = javaMethodID
+            return javaMethodID
+        }
+    }
+    
     public func getJavaField(forClass className: String, field: String, sig: String) throws -> jfieldID {
         let key = "\(className).\(field)\(sig)"
         let javaClass = try getJavaClass(className)

Sources/JavaEncoder.swift

@@ -410,8 +410,11 @@ class JavaEnumValueEncodingContainer: SingleValueEncodingContainer {
         let clazz = try JNI.getJavaClass(javaClass)
         // If jniStorage.javaObject == nil its enum, else optionSet
         if jniStorage.javaObject == nil {
-            let valueOfMethodID = JNI.api.GetStaticMethodID(JNI.env, clazz, "valueOf", "(\(rawValue.type.sig))L\(javaClass);")
+            let valueOfMethodID = try JNI.getStaticJavaMethod(forClass: javaClass, method: "valueOf", sig: "(\(rawValue.type.sig))L\(javaClass);")
-            jniStorage.javaObject = JNI.CallStaticObjectMethod(clazz, methodID: valueOfMethodID!, args: [jvalue(l: rawValue.javaObject)])!
+            guard let javaObject = JNI.CallStaticObjectMethod(clazz, methodID: valueOfMethodID, args: [jvalue(l: rawValue.javaObject)]) else {
+                throw JavaCodingError.nilNotSupported("\(javaClass).valueOf()")
+            }
+            jniStorage.javaObject = javaObject
         }
         else {
             let filed = try JNI.getJavaField(forClass: self.javaClass, field: "rawValue", sig: rawValue.type.sig)
@@ -517,6 +520,8 @@ extension JavaEncoder {
             let fullClassName = package  + "/" + String(describing: type(of: value))
             // We don't create object for enum. Should be created at JavaEnumValueEncodingContainer
             storage = JNIStorageObject(type: .object(className: fullClassName))
+            javaObjects.append(storage)
+            try value.encode(to: self)
         }
         else {
             let storageType: JNIStorageType