private static void mapLines(
     TextBuffer code,
     StructLineNumberTableAttribute table,
     BytecodeMappingTracer tracer,
     int startLine) {
   // build line start offsets map
   HashMap<Integer, Set<Integer>> lineStartOffsets = new HashMap<Integer, Set<Integer>>();
   for (Map.Entry<Integer, Integer> entry : tracer.getMapping().entrySet()) {
     Integer lineNumber = entry.getValue() - startLine;
     Set<Integer> curr = lineStartOffsets.get(lineNumber);
     if (curr == null) {
       curr = new TreeSet<Integer>(); // requires natural sorting!
     }
     curr.add(entry.getKey());
     lineStartOffsets.put(lineNumber, curr);
   }
   String lineSeparator = DecompilerContext.getNewLineSeparator();
   StringBuilder text = code.getOriginalText();
   int pos = text.indexOf(lineSeparator);
   int lineNumber = 0;
   while (pos != -1) {
     Set<Integer> startOffsets = lineStartOffsets.get(lineNumber);
     if (startOffsets != null) {
       for (Integer offset : startOffsets) {
         int number = table.findLineNumber(offset);
         if (number >= 0) {
           code.setLineMapping(number, pos);
           break;
         }
       }
     }
     pos = text.indexOf(lineSeparator, pos + 1);
     lineNumber++;
   }
 }
  private boolean methodToJava(
      ClassNode node,
      StructMethod mt,
      TextBuffer buffer,
      int indent,
      BytecodeMappingTracer tracer) {
    ClassWrapper wrapper = node.getWrapper();
    StructClass cl = wrapper.getClassStruct();
    MethodWrapper methodWrapper = wrapper.getMethodWrapper(mt.getName(), mt.getDescriptor());

    boolean hideMethod = false;
    int start_index_method = buffer.length();

    MethodWrapper outerWrapper =
        (MethodWrapper) DecompilerContext.getProperty(DecompilerContext.CURRENT_METHOD_WRAPPER);
    DecompilerContext.setProperty(DecompilerContext.CURRENT_METHOD_WRAPPER, methodWrapper);

    try {
      boolean isInterface = cl.hasModifier(CodeConstants.ACC_INTERFACE);
      boolean isAnnotation = cl.hasModifier(CodeConstants.ACC_ANNOTATION);
      boolean isEnum =
          cl.hasModifier(CodeConstants.ACC_ENUM)
              && DecompilerContext.getOption(IFernflowerPreferences.DECOMPILE_ENUM);
      boolean isDeprecated = mt.getAttributes().containsKey("Deprecated");
      boolean clinit = false, init = false, dinit = false;

      MethodDescriptor md = MethodDescriptor.parseDescriptor(mt.getDescriptor());

      int flags = mt.getAccessFlags();
      if ((flags & CodeConstants.ACC_NATIVE) != 0) {
        flags &=
            ~CodeConstants
                .ACC_STRICT; // compiler bug: a strictfp class sets all methods to strictfp
      }
      if (CodeConstants.CLINIT_NAME.equals(mt.getName())) {
        flags &=
            CodeConstants
                .ACC_STATIC; // ignore all modifiers except 'static' in a static initializer
      }

      if (isDeprecated) {
        appendDeprecation(buffer, indent);
      }

      if (interceptor != null) {
        String oldName =
            interceptor.getOldName(
                cl.qualifiedName + " " + mt.getName() + " " + mt.getDescriptor());
        appendRenameComment(buffer, oldName, MType.METHOD, indent);
      }

      boolean isSynthetic =
          (flags & CodeConstants.ACC_SYNTHETIC) != 0 || mt.getAttributes().containsKey("Synthetic");
      boolean isBridge = (flags & CodeConstants.ACC_BRIDGE) != 0;
      if (isSynthetic) {
        appendComment(buffer, "synthetic method", indent);
      }
      if (isBridge) {
        appendComment(buffer, "bridge method", indent);
      }

      appendAnnotations(buffer, mt, indent);

      buffer.appendIndent(indent);

      appendModifiers(buffer, flags, METHOD_ALLOWED, isInterface, METHOD_EXCLUDED);

      if (isInterface && mt.containsCode()) {
        // 'default' modifier (Java 8)
        buffer.append("default ");
      }

      String name = mt.getName();
      if (CodeConstants.INIT_NAME.equals(name)) {
        if (node.type == ClassNode.CLASS_ANONYMOUS) {
          name = "";
          dinit = true;
        } else {
          name = node.simpleName;
          init = true;
        }
      } else if (CodeConstants.CLINIT_NAME.equals(name)) {
        name = "";
        clinit = true;
      }

      GenericMethodDescriptor descriptor = null;
      if (DecompilerContext.getOption(IFernflowerPreferences.DECOMPILE_GENERIC_SIGNATURES)) {
        StructGenericSignatureAttribute attr =
            (StructGenericSignatureAttribute) mt.getAttributes().getWithKey("Signature");
        if (attr != null) {
          descriptor = GenericMain.parseMethodSignature(attr.getSignature());
          if (descriptor != null) {
            int actualParams = md.params.length;
            List<VarVersionPair> sigFields = methodWrapper.signatureFields;
            if (sigFields != null) {
              actualParams = 0;
              for (VarVersionPair field : methodWrapper.signatureFields) {
                if (field == null) {
                  actualParams++;
                }
              }
            } else if (isEnum && init) actualParams -= 2;
            if (actualParams != descriptor.params.size()) {
              String message =
                  "Inconsistent generic signature in method "
                      + mt.getName()
                      + " "
                      + mt.getDescriptor()
                      + " in "
                      + cl.qualifiedName;
              DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.Severity.WARN);
              descriptor = null;
            }
          }
        }
      }

      boolean throwsExceptions = false;
      int paramCount = 0;

      if (!clinit && !dinit) {
        boolean thisVar = !mt.hasModifier(CodeConstants.ACC_STATIC);

        if (descriptor != null && !descriptor.fparameters.isEmpty()) {
          appendTypeParameters(buffer, descriptor.fparameters, descriptor.fbounds);
          buffer.append(' ');
        }

        if (!init) {
          if (descriptor != null) {
            buffer.append(GenericMain.getGenericCastTypeName(descriptor.ret));
          } else {
            buffer.append(ExprProcessor.getCastTypeName(md.ret));
          }
          buffer.append(' ');
        }

        buffer.append(toValidJavaIdentifier(name));
        buffer.append('(');

        // parameters
        List<VarVersionPair> signFields = methodWrapper.signatureFields;

        int lastVisibleParameterIndex = -1;
        for (int i = 0; i < md.params.length; i++) {
          if (signFields == null || signFields.get(i) == null) {
            lastVisibleParameterIndex = i;
          }
        }

        boolean firstParameter = true;
        int index = isEnum && init ? 3 : thisVar ? 1 : 0;
        boolean hasDescriptor = descriptor != null;
        int start = isEnum && init && !hasDescriptor ? 2 : 0;
        int params = hasDescriptor ? descriptor.params.size() : md.params.length;
        for (int i = start; i < params; i++) {
          if (hasDescriptor || (signFields == null || signFields.get(i) == null)) {
            if (!firstParameter) {
              buffer.append(", ");
            }

            appendParameterAnnotations(buffer, mt, paramCount);

            if (methodWrapper.varproc.getVarFinal(new VarVersionPair(index, 0))
                == VarTypeProcessor.VAR_EXPLICIT_FINAL) {
              buffer.append("final ");
            }

            if (descriptor != null) {
              GenericType parameterType = descriptor.params.get(i);

              boolean isVarArg =
                  (i == lastVisibleParameterIndex
                      && mt.hasModifier(CodeConstants.ACC_VARARGS)
                      && parameterType.arrayDim > 0);
              if (isVarArg) {
                parameterType = parameterType.decreaseArrayDim();
              }

              String typeName = GenericMain.getGenericCastTypeName(parameterType);
              if (ExprProcessor.UNDEFINED_TYPE_STRING.equals(typeName)
                  && DecompilerContext.getOption(
                      IFernflowerPreferences.UNDEFINED_PARAM_TYPE_OBJECT)) {
                typeName = ExprProcessor.getCastTypeName(VarType.VARTYPE_OBJECT);
              }

              buffer.append(typeName);

              if (isVarArg) {
                buffer.append("...");
              }
            } else {
              VarType parameterType = md.params[i];

              boolean isVarArg =
                  (i == lastVisibleParameterIndex
                      && mt.hasModifier(CodeConstants.ACC_VARARGS)
                      && parameterType.arrayDim > 0);
              if (isVarArg) {
                parameterType = parameterType.decreaseArrayDim();
              }

              String typeName = ExprProcessor.getCastTypeName(parameterType);
              if (ExprProcessor.UNDEFINED_TYPE_STRING.equals(typeName)
                  && DecompilerContext.getOption(
                      IFernflowerPreferences.UNDEFINED_PARAM_TYPE_OBJECT)) {
                typeName = ExprProcessor.getCastTypeName(VarType.VARTYPE_OBJECT);
              }

              buffer.append(typeName);

              if (isVarArg) {
                buffer.append("...");
              }
            }

            buffer.append(' ');
            String parameterName = methodWrapper.varproc.getVarName(new VarVersionPair(index, 0));
            buffer.append(
                parameterName == null
                    ? "param" + index
                    : parameterName); // null iff decompiled with errors

            firstParameter = false;
            paramCount++;
          }

          index += md.params[i].stackSize;
        }

        buffer.append(')');

        StructExceptionsAttribute attr =
            (StructExceptionsAttribute) mt.getAttributes().getWithKey("Exceptions");
        if ((descriptor != null && !descriptor.exceptions.isEmpty()) || attr != null) {
          throwsExceptions = true;
          buffer.append(" throws ");

          for (int i = 0; i < attr.getThrowsExceptions().size(); i++) {
            if (i > 0) {
              buffer.append(", ");
            }
            if (descriptor != null && !descriptor.exceptions.isEmpty()) {
              GenericType type = descriptor.exceptions.get(i);
              buffer.append(GenericMain.getGenericCastTypeName(type));
            } else {
              VarType type = new VarType(attr.getExcClassname(i, cl.getPool()), true);
              buffer.append(ExprProcessor.getCastTypeName(type));
            }
          }
        }
      }

      tracer.incrementCurrentSourceLine(buffer.countLines(start_index_method));

      if ((flags & (CodeConstants.ACC_ABSTRACT | CodeConstants.ACC_NATIVE))
          != 0) { // native or abstract method (explicit or interface)
        if (isAnnotation) {
          StructAnnDefaultAttribute attr =
              (StructAnnDefaultAttribute) mt.getAttributes().getWithKey("AnnotationDefault");
          if (attr != null) {
            buffer.append(" default ");
            buffer.append(
                attr.getDefaultValue()
                    .toJava(indent + 1, new BytecodeMappingTracer())); // dummy tracer
          }
        }

        buffer.append(';');
        buffer.appendLineSeparator();
        tracer.incrementCurrentSourceLine();
      } else {
        if (!clinit && !dinit) {
          buffer.append(' ');
        }

        // We do not have line information for method start, lets have it here for now
        StructLineNumberTableAttribute lineNumberTable =
            (StructLineNumberTableAttribute)
                mt.getAttributes().getWithKey(StructGeneralAttribute.ATTRIBUTE_LINE_NUMBER_TABLE);
        if (lineNumberTable != null
            && DecompilerContext.getOption(IFernflowerPreferences.USE_DEBUG_LINE_NUMBERS)) {
          buffer.setCurrentLine(lineNumberTable.getFirstLine() - 1);
        }
        buffer.append('{').appendLineSeparator();
        tracer.incrementCurrentSourceLine();

        RootStatement root = wrapper.getMethodWrapper(mt.getName(), mt.getDescriptor()).root;

        if (root != null && !methodWrapper.decompiledWithErrors) { // check for existence
          try {
            int startLine = tracer.getCurrentSourceLine();

            TextBuffer code = root.toJava(indent + 1, tracer);

            hideMethod =
                (clinit || dinit || hideConstructor(wrapper, init, throwsExceptions, paramCount))
                    && code.length() == 0;

            if (!hideMethod
                && lineNumberTable != null
                && DecompilerContext.getOption(IFernflowerPreferences.USE_DEBUG_LINE_NUMBERS)) {
              mapLines(code, lineNumberTable, tracer, startLine);
            }

            buffer.append(code);
          } catch (Throwable ex) {
            DecompilerContext.getLogger()
                .writeMessage(
                    "Method " + mt.getName() + " " + mt.getDescriptor() + " couldn't be written.",
                    ex);
            methodWrapper.decompiledWithErrors = true;
          }
        }

        if (methodWrapper.decompiledWithErrors) {
          buffer.appendIndent(indent + 1);
          buffer.append("// $FF: Couldn't be decompiled");
          buffer.appendLineSeparator();
          tracer.incrementCurrentSourceLine();
        }

        if (root != null) {
          tracer.addMapping(root.getDummyExit().bytecode);
        }
        buffer.appendIndent(indent).append('}').appendLineSeparator();
        tracer.incrementCurrentSourceLine();
      }
    } finally {
      DecompilerContext.setProperty(DecompilerContext.CURRENT_METHOD_WRAPPER, outerWrapper);
    }

    // save total lines
    // TODO: optimize
    // tracer.setCurrentSourceLine(buffer.countLines(start_index_method));

    return !hideMethod;
  }