fix: improve disassemble view for java-input

jadx-plugins/jadx-java-input/src/main/java/jadx/plugins/input/java/data/code/JavaCodeReader.java

@@ -61,15 +61,16 @@ public class JavaCodeReader implements ICodeReader {
 		state.setInsn(insn);
 		int offset = 0;
 		while (offset < codeSize) {
+			insn.setDecoded(false);
+			insn.setOffset(offset);
+			insn.setInsnStart(reader.getOffset());
+
 			int opcode = reader.readU1();
 			JavaInsnInfo insnInfo = JavaInsnsRegister.get(opcode);
 			if (insnInfo == null) {
 				throw new JavaClassParseException("Unknown opcode: 0x" + Integer.toHexString(opcode));
 			}
-			insn.setDecoded(false);
 			insn.setInsnInfo(insnInfo);
-			insn.setInsnStart(reader.getOffset());
-			insn.setOffset(offset);
 			insn.setInsnInfo(insnInfo);
 			insn.setRegsCount(insnInfo.getRegsCount());
 			insn.setOpcode(insnInfo.getApiOpcode());

jadx-plugins/jadx-java-input/src/main/java/jadx/plugins/input/java/data/code/JavaInsnData.java

@@ -12,6 +12,7 @@ import jadx.api.plugins.input.insns.InsnIndexType;
 import jadx.api.plugins.input.insns.Opcode;
 import jadx.api.plugins.input.insns.custom.ICustomPayload;
 import jadx.plugins.input.java.data.ConstPoolReader;
+import jadx.plugins.input.java.data.DataReader;
 import jadx.plugins.input.java.data.code.decoders.IJavaInsnDecoder;
 
 public class JavaInsnData implements InsnData {
@@ -74,9 +75,21 @@ public class JavaInsnData implements InsnData {
 		this.opcode = opcode;
 	}
 
+	@Override
+	public String getOpcodeMnemonic() {
+		return insnInfo.getName();
+	}
+
 	@Override
 	public byte[] getByteCode() {
-		return new byte[0];
+		DataReader reader = state.reader();
+		int startOffset = reader.getOffset();
+		try {
+			reader.absPos(insnStart);
+			return reader.readBytes(1 + payloadSize);
+		} finally {
+			reader.absPos(startOffset);
+		}
 	}
 
 	@Override

jadx-plugins/jadx-java-input/src/main/java/jadx/plugins/input/java/utils/DisasmUtils.java

@@ -3,27 +3,42 @@ package jadx.plugins.input.java.utils;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 import java.util.concurrent.TimeUnit;
 
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.util.TraceClassVisitor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public class DisasmUtils {
 	private static final Logger LOG = LoggerFactory.getLogger(DisasmUtils.class);
 
+	public static String get(byte[] bytes) {
+		return useASM(bytes);
+	}
+
+	private static String useASM(byte[] bytes) {
+		StringWriter out = new StringWriter();
+		TraceClassVisitor tcv = new TraceClassVisitor(new PrintWriter(out));
+		new ClassReader(bytes).accept(tcv, 0);
+		return out.toString();
+	}
+
 	/**
 	 * Use javap as a temporary disassembler for java bytecode
+	 * Don't remove! Useful for debug.
 	 */
-	public static String get(byte[] bytes) {
+	private static String useSystemJavaP(byte[] bytes) {
 		try {
 			Path tmpCls = null;
 			try {
 				tmpCls = Files.createTempFile("jadx", ".class");
 				Files.write(tmpCls, bytes, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING);
-
 				Process process = Runtime.getRuntime().exec(new String[] {
 						"javap", "-constants", "-v", "-p", "-c",
 						tmpCls.toAbsolutePath().toString()