support Exception

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

@@ -12,10 +12,8 @@ import haidnor.jvm.util.CodeStream;
 import haidnor.jvm.util.JvmThreadHolder;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.bcel.classfile.LocalVariable;
+import org.apache.bcel.Const;
-import org.apache.bcel.classfile.LocalVariableTable;
+import org.apache.bcel.classfile.*;
-import org.apache.bcel.classfile.Method;
-import org.apache.bcel.classfile.Utility;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -94,11 +92,42 @@ public class JavaExecutionEngine {
         for (int i = 0; i < frame.getCodeLength(); ) {
             Instruction instruction = instructionMap.get(i);
             log.debug("{}│ {}", blank, instruction);
-            instruction.execute(frame);
+            try {
-            if (instruction instanceof RETURN || instruction instanceof ARETURN || instruction instanceof DRETURN || instruction instanceof FRETURN || instruction instanceof IRETURN) {
+                instruction.execute(frame);
-                break;
+                if (instruction instanceof RETURN || instruction instanceof ARETURN || instruction instanceof DRETURN || instruction instanceof FRETURN || instruction instanceof IRETURN) {
+                    break;
+                }
+                i += instruction.offSet();
+            } catch (Exception exception) {
+                Integer handlerPC = null;
+
+                CodeException[] exceptionTable = frame.getMethod().getCode().getExceptionTable();
+                for (CodeException codeException : exceptionTable) {
+                    if (codeException.getStartPC() <= i & i <= codeException.getEndPC()) {
+                        int catchType = codeException.getCatchType();
+                        // 0, if the handler catches any exception, otherwise it points to the exception class which is to be caught.
+                        if (catchType == 0) {
+                            frame.push(new StackValue(Const.T_OBJECT, exception));
+                            handlerPC = codeException.getHandlerPC();
+                        } else {
+                            String exceptionClassName = frame.getConstantPoolUtil().getConstantClassClassName(catchType);
+                            exceptionClassName = Utility.compactClassName(exceptionClassName, false);
+                            Class<?> exceptionClass = Class.forName(exceptionClassName);
+                            if (exceptionClass.isAssignableFrom(exception.getClass())) {
+                                frame.push(new StackValue(Const.T_OBJECT, exception));
+                                handlerPC = codeException.getHandlerPC();
+                            }
+                        }
+                    }
+                }
+                if (handlerPC != null) {
+                    i = handlerPC;
+                } else {
+                    log.debug("{}└──────────────────[{}] No Exception Handler Return!", blank, stackSize);
+                    throw exception;
+                }
             }
-            i += instruction.offSet();
+
         }
 
         log.debug("{}└──────────────────[{}] {} | {}", blank, stackSize, frame.klass.getClassName(), frame.getMethod());

src/main/java/haidnor/jvm/instruction/references/ANEWARRAY.java

@@ -30,7 +30,7 @@ public class ANEWARRAY extends Instruction {
         ConstantPool constantPool = frame.getConstantPool();
         ConstantPoolUtil constantPoolUtil = frame.getConstantPoolUtil();
         ConstantClass constantClass = constantPool.getConstant(constantClassIndex);
-        String className = constantPoolUtil.getClassName(constantClass);
+        String className = constantPoolUtil.getConstantClassClassName(constantClass);
 
         Klass klass = Metaspace.getJavaClass(Utility.compactClassName(className));
         if (klass == null) {

src/main/java/haidnor/jvm/instruction/references/ATHROW.java

@@ -2,6 +2,7 @@ package haidnor.jvm.instruction.references;
 
 import haidnor.jvm.instruction.Instruction;
 import haidnor.jvm.runtime.Frame;
+import haidnor.jvm.runtime.StackValue;
 import haidnor.jvm.util.CodeStream;
 import lombok.SneakyThrows;
 
@@ -14,7 +15,8 @@ public class ATHROW extends Instruction {
     @Override
     @SneakyThrows
     public void execute(Frame frame) {
-
+        StackValue pop = frame.pop();
+        throw (Exception) pop.getValue();
     }
 
 }

src/main/java/haidnor/jvm/instruction/references/INSTANCEOF.java

@@ -30,7 +30,7 @@ public class INSTANCEOF extends Instruction {
         ConstantPool constantPool = frame.getConstantPool();
         ConstantPoolUtil constantPoolUtil = frame.getConstantPoolUtil();
         ConstantClass constantClass = constantPool.getConstant(constantClassIndex);
-        String className = constantPoolUtil.getClassName(constantClass);
+        String className = constantPoolUtil.getConstantClassClassName(constantClass);
         className = Utility.compactClassName(className);
 
         StackValue stackValue = frame.pop();

src/main/java/haidnor/jvm/instruction/references/NEW.java

@@ -29,7 +29,7 @@ public class NEW extends Instruction {
         ConstantPool constantPool = frame.getConstantPool();
         ConstantPoolUtil constantPoolUtil = frame.getConstantPoolUtil();
         ConstantClass constantClass = constantPool.getConstant(constantClassIndex);
-        String className = constantPoolUtil.getClassName(constantClass);
+        String className = constantPoolUtil.getConstantClassClassName(constantClass);
 
         if (className.startsWith("java/")) {
             frame.push(new StackValue(Const.T_OBJECT, null));

src/main/java/haidnor/jvm/util/ConstantPoolUtil.java

@@ -42,16 +42,16 @@ public class ConstantPoolUtil {
     /**
      * 获取长类名, 例如 java/lang/String
      */
-    public String getClassName(final ConstantClass constantClass) {
+    public String getConstantClassClassName(final ConstantClass constantClass) {
         ConstantUtf8 constantUtf8 = cp.getConstant(constantClass.getNameIndex());
         return constantUtf8.getBytes();
     }
     /**
      * 获取长类名, 例如 java/lang/String
      */
-    public String getClassName(int index) {
+    public String getConstantClassClassName(int constantClassIndex) {
-        ConstantClass constantClass = cp.getConstant(index);
+        ConstantClass constantClass = cp.getConstant(constantClassIndex);
-        return getClassName(constantClass);
+        return getConstantClassClassName(constantClass);
     }
 
 

src/test/java/haidnor/jvm/test/demo/Demo7.java

@@ -4,17 +4,17 @@ package haidnor.jvm.test.demo;
 public class Demo7 {
 
     public static void main(String[] args) {
-        String fun = fun();
-        System.out.println(fun);
-    }
-
-    public static String fun() {
-        String str = "hello";
         try {
-            return str;
+            String name = fun();
-        } finally {
+            System.out.println(name);
-            System.out.println("zhangsan");
+        } catch (Exception exception) {
+            System.out.println("计算错误");
         }
     }
 
+    public static String fun() {
+        System.out.println(1 / 0);
+        return "zhangsan";
+    }
+
 }