ReplaceIcon.java

// TODO: This successfully replaces the icon but the EXE won't run afterwards

package com.company;

import com.kichik.pecoff4j.PE;
import com.kichik.pecoff4j.ResourceDirectory;
import com.kichik.pecoff4j.ResourceDirectoryTable;
import com.kichik.pecoff4j.ResourceEntry;
import com.kichik.pecoff4j.constant.ResourceType;
import com.kichik.pecoff4j.io.DataReader;
import com.kichik.pecoff4j.io.DataWriter;
import com.kichik.pecoff4j.io.PEParser;
import com.kichik.pecoff4j.resources.GroupIconDirectory;
import com.kichik.pecoff4j.resources.GroupIconDirectoryEntry;
import com.kichik.pecoff4j.resources.IconDirectoryEntry;
import com.kichik.pecoff4j.resources.IconImage;
import com.kichik.pecoff4j.util.IconFile;
import com.kichik.pecoff4j.util.PaddingType;

import java.io.*;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

public class ReplaceIcon {

    public static void main(String... args) throws IOException {
        String inputExePath = "/Users/owner/tray/out/jlink/jdk-bellsoft-aarch64-windows-25.37.0/jdk-25/bin/java.exe";
        String newIconPath = "/Users/owner/tray/assets/branding/windows-icon.ico";
        String outputExePath = "/Users/owner/Desktop/java_qz2.exe";

        replaceIcon(inputExePath, newIconPath, outputExePath);
    }

    // Any value should work, but 0 is what java.exe used when testing
    private static final int ICON_ID = 1033;

    // Any value should work, but 2000 is what java.exe used when testing
    private static final int GROUP_ID = 2000;

    public static void replaceIcon(String inputExePath, String newIconPath, String outputExePath) throws IOException {
        // 1. Parse the existing executable file
        System.out.println("Parsing input EXE: " + inputExePath);
        PE pe = PEParser.parse(new FileInputStream(inputExePath));
        ResourceDirectory directory = pe.getImageData().getResourceTable();

        if (directory == null) {
            System.err.println("Error: Executable has no resource table to modify.");
            return;
        }

        // 2. Load the new icon file (.ico)
        System.out.println("Loading new icon: " + newIconPath);
        IconFile iconFile = IconFile.read(new DataReader(new FileInputStream(newIconPath)));

        // TODO: REMOVE THIS: Try to debug existing layout
        System.out.println("### BEFORE:\n");
        debugDirectory(directory, "");

        // 3. Remove existing icon resources (Type 3: ICON, Type 14: GROUP_ICON)
        System.out.println("Removing existing icon resources...");
        directory.getEntries().removeIf(
                entry -> entry.getId() == ResourceType.ICON ||
                        entry.getId() == ResourceType.GROUP_ICON
        );



        // 4. Add the new ICON entries (Resource Type 3)
        // Each image in the ICO file becomes a separate ICON resource
        List<ResourceEntry> iconEntries = new ArrayList<>();

        for (IconDirectoryEntry entry : iconFile.getDirectory().getEntries()) {
            // The directory structure for an ICON resource is: Type 3 -> Icon ID -> Raw Icon Data
            iconEntries.add(entry(iconEntries.size() + 1,
                    directory(entry(ICON_ID, iconFile.getImage(entry).toByteArray()))));
        }
        // Add ICON in index 0 (seems to fix preview in explorer)
        directory.getEntries().add(0, entry(ResourceType.ICON,
                directory(iconEntries.toArray(new ResourceEntry[0]))));

        // 5. Add the new GROUP_ICON entry (Resource Type 14)
        // This directory acts as the 'pointer' to the individual ICON resources
        System.out.println("Adding new GROUP_ICON resource...");
        byte[] iconDirData = createIconDirectory(iconFile).toByteArray();
        // The directory structure for GROUP_ICON is: Type 14 -> Icon Index (usually 1) -> Group Icon Directory Data
        // Add GROUP_ICON in index 1 (seems to fix preview in explorer)
        directory.getEntries().add(1, entry(ResourceType.GROUP_ICON,
                directory(entry(GROUP_ID, directory(entry(ICON_ID, iconDirData))))));

        // 6. Rebuild the PE structure and update offsets
        System.out.println("Rebuilding PE structure...");
        pe.rebuild(PaddingType.PATTERN);
        //pe.rebuild(PaddingType.ZEROS);

        // TODO: REMOVE THIS: Try to debug existing layout
        System.out.println("### AFTER:\n");
        debugDirectory(directory, "");

        // 7. Write the modified PE to a new file
        System.out.println("Writing modified EXE to: " + outputExePath);
        DataWriter writer = new DataWriter(new FileOutputStream(outputExePath));
        pe.write(writer);

        System.out.println("Icon replacement complete!");
    }

    // --- Helper methods copied and simplified from ResourceDirectoryTest ---
    private static GroupIconDirectory createIconDirectory(IconFile iconFile) {
        GroupIconDirectory directory = new GroupIconDirectory();
        directory.setReserved(0);
        directory.setType(1); // 1 for ICON

        int id = 1;
        for (IconDirectoryEntry iconEntry : iconFile.getDirectory().getEntries()) {
            IconImage icon = iconFile.getImage(iconEntry);
            if(icon.getHeader() == null) continue;
            GroupIconDirectoryEntry entry = new GroupIconDirectoryEntry();
            entry.setWidth(icon.getHeader().getWidth());
            // The height in the GroupIconDirectory is half the height in the BITMAPINFOHEADER (part of IconImage)
            entry.setHeight(icon.getHeader().getHeight() / 2);
            entry.setColorCount(0); // If 0, actual color count is stored elsewhere
            entry.setReserved(0);
            entry.setPlanes(icon.getHeader().getPlanes());
            entry.setBitCount(icon.getHeader().getBitCount());
            entry.setBytesInRes(icon.sizeOf());
            entry.setId(id++); // Reference ID to the individual ICON resource (Type 3)
            directory.getEntries().add(entry);
        }
        return directory;
    }

    private static ResourceEntry entry(int id, ResourceDirectory directory) {
        ResourceEntry entry = new ResourceEntry();
        entry.setId(id);
        entry.setDirectory(directory);
        return entry;
    }

    private static ResourceEntry entry(int id, byte[] data) {
        ResourceEntry entry = new ResourceEntry();
        entry.setId(id);
        entry.setCodePage(1252); // Default Windows ANSI code page
        entry.setData(data);
        return entry;
    }

    private static ResourceDirectory directory(ResourceEntry... entries) {
        ResourceDirectory dir = new ResourceDirectory();
        ResourceDirectoryTable table = new ResourceDirectoryTable();
        table.setMajorVersion(4);
        dir.setTable(table);
        for (ResourceEntry entry : entries) {
            dir.getEntries().add(entry);
        }
        return dir;
    }

    private static String getResourceType(int i) {
        // Check resource classifications
        for(Field f : ResourceType.class.getFields()) {
            try {
                if (i == f.getInt(null)) {
                    return f.getName() + " (" + i + ")";
                }
            } catch(IllegalArgumentException | IllegalAccessException e) {
                e.printStackTrace();
            }
        }

        // Check language
        switch(i) {
            case 1025: return "Arabic" + " (" + i + ")";
            case 1026: return "Bulgarian - Cyrillic" + " (" + i + ")";
            case 1027: return "Catalan" + " (" + i + ")";
            case 1028: return "Traditional Chinese Taiwan" + " (" + i + ")";
            case 1029: return "Czech" + " (" + i + ")";
            case 1030: return "Danish Norwegian" + " (" + i + ")";
            case 1031: return "German Standard (Germany)" + " (" + i + ")";
            case 1032: return "Greek" + " (" + i + ")";
            case 1033: return "English (United States)" + " (" + i + ")";
            case 1035: return "Finnish Swedish (Finland)" + " (" + i + ")";
            case 1036: return "French (France)" + " (" + i + ")";
            case 1037: return "Hebrew" + " (" + i + ")";
            case 1038: return "Hungarian" + " (" + i + ")";
            case 1040: return "Italian (Italy)" + " (" + i + ")";
            case 1041: return "Japanese - Stoke" + " (" + i + ")";
            case 1042: return "Korean" + " (" + i + ")";
            case 1043: return "Dutch (Netherlands)" + " (" + i + ")";
            case 1044: return "Danish Norwegian - Bokmaal" + " (" + i + ")";
            case 1045: return "Polish" + " (" + i + ")";
            case 1046: return "Brazilian Portuguese" + " (" + i + ")";
            case 1048: return "Romanian" + " (" + i + ")";
            case 1049: return "Russian (Russia) - Cyrillic" + " (" + i + ")";
            case 1050: return "Croatian" + " (" + i + ")";
            case 1051: return "Slovak" + " (" + i + ")";
            case 1053: return "Finnish Swedish (Sweden)" + " (" + i + ")";
            case 1054: return "Thai" + " (" + i + ")";
            case 1055: return "Turkish" + " (" + i + ")";
            case 1057: return "Indonesian" + " (" + i + ")";
            case 1058: return "Ukrainian" + " (" + i + ")";
            case 1060: return "Slovenian" + " (" + i + ")";
            case 1061: return "Estonian" + " (" + i + ")";
            case 1062: return "Latvian" + " (" + i + ")";
            case 1063: return "Lithuanian" + " (" + i + ")";
            case 1066: return "Vietnamese" + " (" + i + ")";
            case 1069: return "Basque" + " (" + i + ")";
            case 1081: return "Hindi - Latin character" + " (" + i + ")";
            case 1086: return "Malay" + " (" + i + ")";
            case 1087: return "Kazakh" + " (" + i + ")";
            case 1110: return "Galician" + " (" + i + ")";
            case 2052: return "Simplified Chinese (China)" + " (" + i + ")";
            case 2070: return "Portuguese (Portugal)" + " (" + i + ")";
            case 2074: return "Serbian - Latin character set" + " (" + i + ")";
            case 3076: return "Traditional Chinese Hong Kong" + " (" + i + ")";
            case 3082: return "Modern Spanish (Spain)" + " (" + i + ")";
            case 3098: return "Serbian - Cyrillic" + " (" + i + ")";
        }

        return "[" + i + "]"; // fallback, assume key id
    }



    private static void debugDirectory(ResourceDirectory directory, String indent) {
        // DEBUG
        for(ResourceEntry entry : directory.getEntries()) {
            if(entry.getDirectory() != null) {
                System.out.println(indent + "- " + getResourceType(entry.getId()));
                debugDirectory(entry.getDirectory(), " " + indent);
            } else {
                System.out.println(indent + "  - " + getResourceType(entry.getId()));
            }
            /*switch(entry.getId()) {
                case ResourceType.ICON:
                    //System.out.println(entry.getId() + ": " + (entry.getData() == null ? null : entry.getData().length));
                    break;
                case ResourceType.GROUP_ICON:
                    //System.out.println(entry.getId() + ": " + (entry.getData() == null ? null : entry.getData().length));
                    break;
                default:
            }*/
        }
    }
}