update Klass() 优先加载父类

src/main/java/haidnor/jvm/core/JavaExecutionEngine.java

@@ -27,7 +27,6 @@ public class JavaExecutionEngine {
     public static void callMethod(Frame lastFrame, KlassMethod klassMethod) {
         JvmThread jvmThread = JvmThreadHolder.get();
         Frame newFrame = new Frame(jvmThread, klassMethod);
-
         // 如果有上一个栈帧, 代表需要传参
         if (lastFrame != null) {
             Method method = klassMethod.javaMethod;

src/main/java/haidnor/jvm/rtda/heap/Klass.java

@@ -44,6 +44,14 @@ public class Klass {
      */
     private Map<String, KlassField> staticFieldMap = new HashMap<>();
 
+    /**
+     * 加载类元数据并将类放入元空间
+     * <p>
+     * 执行顺序如下
+     * 1.优先加载父类
+     * 2.为类元数据创建静态字段(此时并没有给静态字符赋值)
+     * 3.执行 clinit 方法(静态方法), 为静态字段赋值,或执行自定义逻辑.
+     */
     @SneakyThrows
     public Klass(ClassLoader classLoader, JavaClass javaClass) {
         this.javaClass = javaClass;
@@ -51,6 +59,14 @@ public class Klass {
         this.className = javaClass.getClassName();
         this.superClassName = javaClass.getSuperclassName();
 
+        // loader super class
+        JavaClass superJavaClass = javaClass.getSuperClass();
+        if (superJavaClass != null) {
+            this.superKlass = new Klass(classLoader, superJavaClass);
+        }
+
+        Metaspace.registerJavaClass(this);
+
         // init staticFieldMap
         for (Field field : javaClass.getFields()) {
             if (field.isStatic()) {
@@ -58,8 +74,6 @@ public class Klass {
             }
         }
 
-        Metaspace.registerJavaClass(this);
-
         // execute <clinit> method
         if (!javaClass.getClassName().startsWith("java.")) {
             for (Method method : javaClass.getMethods()) {
@@ -70,12 +84,6 @@ public class Klass {
                 }
             }
         }
-
-        // loader super class
-        JavaClass superJavaClass = javaClass.getSuperClass();
-        if (superJavaClass != null) {
-            this.superKlass = new Klass(classLoader, superJavaClass);
-        }
     }
 
     public KlassField getStaticField(String filedName) {

src/test/java/haidnor/jvm/test/clazz/Human.java

@@ -2,7 +2,14 @@ package haidnor.jvm.test.clazz;
 
 public class Human {
 
+    public static final String HUMAN_NAME = "123";
+
+    static {
+        System.out.println("Human 类被加载了");
+    }
+
     public void eat() {
+        Object o = new Object();
         System.out.println("人类吃饭");
     }
 

src/test/java/haidnor/jvm/test/clazz/Student.java

@@ -6,6 +6,11 @@ public class Student extends Human {
 
     public static String school = "Hello World!";
 
+    static {
+        System.out.println(HUMAN_NAME);
+        System.out.println("student 类被加载了");
+    }
+
     public void method1() {
         System.out.println("method1");
         method2();