diff --git a/README.md b/README.md
index f490261..21e2b96 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,14 @@ Allow [MultiMC](https://github.com/MultiMC/MultiMC5) to launch Minecraft 1.13+ w
 
 **ForgeWrapper has been adopted by MultiMC, you do not need to perform the following steps manually. (2020-03-29)**
 
+## For other launchers
+1. ForgeWrapper provides some java properties since 1.4.2:
+   - `forgewrapper.librariesDir` : a path to libraries folder (e.g. -Dforgewrapper.librariesDir=/home/xxx/.minecraft/libraries)
+   - `forgewrapper.installer` : a path to forge installer (e.g. -Dforgewrapper.installer=/home/xxx/forge-1.14.4-28.2.0-installer.jar)
+   - `forgewrapper.minecraft` : a path to the vanilla minecraft jar (e.g. -Dforgewrapper.minecraft=/home/xxx/.minecraft/versions/1.14.4/1.14.4.jar)
+
+2. ForgeWrapper also provides an interface [`IFileDetector`](https://github.com/ZekerZhayard/ForgeWrapper/blob/master/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/IFileDetector.java), you can implement it and custom your own detecting rules. To load it, you should make another jar which contains `META-INF/services/io.github.zekerzhayard.forgewrapper.installer.detector.IFileDetector` within the full implementation class name and add the jar to class path.
+
 ## How to use (Outdated)
 
 1. Download Forge installer for Minecraft 1.13+ [here](https://files.minecraftforge.net/).
diff --git a/build.gradle b/build.gradle
index c501600..591fddd 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,7 +5,7 @@ apply plugin: "idea"
 
 sourceCompatibility = targetCompatibility = 1.8
 
-version = "1.4.1"
+version = "1.4.2"
 group = "io.github.zekerzhayard"
 archivesBaseName = rootProject.name
 
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/ClientInstall4MultiMC.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/ClientInstall4MultiMC.java
index f2db374..ea72564 100644
--- a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/ClientInstall4MultiMC.java
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/ClientInstall4MultiMC.java
@@ -8,14 +8,17 @@ import net.minecraftforge.installer.actions.ProgressCallback;
 import net.minecraftforge.installer.json.Install;
 
 public class ClientInstall4MultiMC extends ClientInstall {
-    public ClientInstall4MultiMC(Install profile, ProgressCallback monitor) {
+    protected File libraryDir;
+    protected File minecraftJar;
+
+    public ClientInstall4MultiMC(Install profile, ProgressCallback monitor, File libraryDir, File minecraftJar) {
         super(profile, monitor);
+        this.libraryDir = libraryDir;
+        this.minecraftJar = minecraftJar;
     }
 
     @Override
     public boolean run(File target, Predicate<String> optionals) {
-        File librariesDir = Main.getLibrariesDir();
-        File clientTarget = new File(String.format("%s/com/mojang/minecraft/%s/minecraft-%s-client.jar", librariesDir.getAbsolutePath(), this.profile.getMinecraft(), this.profile.getMinecraft()));
-        return this.processors.process(librariesDir, clientTarget);
+        return this.processors.process(this.libraryDir, this.minecraftJar);
     }
 }
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Installer.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Installer.java
index ad60ad7..1a822ce 100644
--- a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Installer.java
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Installer.java
@@ -1,11 +1,13 @@
 package io.github.zekerzhayard.forgewrapper.installer;
 
+import java.io.File;
+
 import net.minecraftforge.installer.actions.ProgressCallback;
 import net.minecraftforge.installer.json.Install;
 import net.minecraftforge.installer.json.Util;
 
 public class Installer {
-    public static boolean install() {
+    public static boolean install(File libraryDir, File minecraftJar) {
         ProgressCallback monitor = ProgressCallback.withOutputs(System.out);
         Install install = Util.loadInstallProfile();
         if (System.getProperty("java.net.preferIPv4Stack") == null) {
@@ -16,6 +18,6 @@ public class Installer {
         String jvmVersion = System.getProperty("java.vm.version", "missing jvm version");
         monitor.message(String.format("JVM info: %s - %s - %s", vendor, javaVersion, jvmVersion));
         monitor.message("java.net.preferIPv4Stack=" + System.getProperty("java.net.preferIPv4Stack"));
-        return new ClientInstall4MultiMC(install, monitor).run(null, input -> true);
+        return new ClientInstall4MultiMC(install, monitor, libraryDir, minecraftJar).run(null, input -> true);
     }
 }
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Main.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Main.java
index bd97c19..c52c272 100644
--- a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Main.java
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/Main.java
@@ -1,7 +1,6 @@
 package io.github.zekerzhayard.forgewrapper.installer;
 
 import java.io.File;
-import java.net.URISyntaxException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.nio.file.Files;
@@ -11,52 +10,46 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import cpw.mods.modlauncher.Launcher;
+import io.github.zekerzhayard.forgewrapper.installer.detector.DetectorLoader;
+import io.github.zekerzhayard.forgewrapper.installer.detector.IFileDetector;
 
 public class Main {
     public static void main(String[] args) throws Exception {
         List<String> argsList = Stream.of(args).collect(Collectors.toList());
         String mcVersion = argsList.get(argsList.indexOf("--fml.mcVersion") + 1);
-        String mcpFullVersion = mcVersion + "-" + argsList.get(argsList.indexOf("--fml.mcpVersion") + 1);
         String forgeFullVersion = mcVersion + "-" + argsList.get(argsList.indexOf("--fml.forgeVersion") + 1);
 
-        Path librariesDir = getLibrariesDir().toPath();
-        Path minecraftDir = librariesDir.resolve("net").resolve("minecraft").resolve("client");
-        Path forgeDir = librariesDir.resolve("net").resolve("minecraftforge").resolve("forge").resolve(forgeFullVersion);
-        if (getAdditionalLibraries(minecraftDir, forgeDir, mcVersion, forgeFullVersion, mcpFullVersion).anyMatch(path -> !Files.exists(path))) {
+        IFileDetector detector = DetectorLoader.loadDetector();
+        if (!detector.checkExtraFiles(forgeFullVersion)) {
             System.out.println("Some extra libraries are missing! Run the installer to generate them now.");
-            URLClassLoader ucl = URLClassLoader.newInstance(new URL[] {
+
+            // Check installer jar.
+            Path installerJar = detector.getInstallerJar(forgeFullVersion);
+            if (!IFileDetector.isFile(installerJar)) {
+                throw new RuntimeException("Can't detect the forge installer!");
+            }
+
+            // Check vanilla Minecraft jar.
+            Path minecraftJar = detector.getMinecraftJar(mcVersion);
+            if (!IFileDetector.isFile(minecraftJar)) {
+                throw new RuntimeException("Can't detect the Minecraft jar!");
+            }
+
+            try (URLClassLoader ucl = URLClassLoader.newInstance(new URL[] {
                 Main.class.getProtectionDomain().getCodeSource().getLocation(),
                 Launcher.class.getProtectionDomain().getCodeSource().getLocation(),
-                forgeDir.resolve("forge-" + forgeFullVersion + "-installer.jar").toUri().toURL()
-            }, getParentClassLoader());
-
-            Class<?> installer = ucl.loadClass("io.github.zekerzhayard.forgewrapper.installer.Installer");
-            if (!(boolean) installer.getMethod("install").invoke(null)) {
-                return;
+                installerJar.toUri().toURL()
+            }, getParentClassLoader())) {
+                Class<?> installer = ucl.loadClass("io.github.zekerzhayard.forgewrapper.installer.Installer");
+                if (!(boolean) installer.getMethod("install", File.class, File.class).invoke(null, detector.getLibraryDir().toFile(), minecraftJar.toFile())) {
+                    return;
+                }
             }
         }
 
         Launcher.main(args);
     }
 
-    public static File getLibrariesDir() {
-        try {
-            File laucnher = new File(Launcher.class.getProtectionDomain().getCodeSource().getLocation().toURI());
-            //              /<version>      /modlauncher    /mods           /cpw            /libraries
-            return laucnher.getParentFile().getParentFile().getParentFile().getParentFile().getParentFile();
-        } catch (URISyntaxException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    public static Stream<Path> getAdditionalLibraries(Path minecraftDir, Path forgeDir, String mcVersion, String forgeFullVersion, String mcpFullVersion) {
-        return Stream.of(
-            forgeDir.resolve("forge-" + forgeFullVersion + "-client.jar"),
-            minecraftDir.resolve(mcVersion).resolve("client-" + mcVersion + "-extra.jar"),
-            minecraftDir.resolve(mcpFullVersion).resolve("client-" + mcpFullVersion + "-srg.jar")
-        );
-    }
-
     // https://github.com/MinecraftForge/Installer/blob/fe18a164b5ebb15b5f8f33f6a149cc224f446dc2/src/main/java/net/minecraftforge/installer/actions/PostProcessors.java#L287-L303
     private static ClassLoader getParentClassLoader() {
         if (!System.getProperty("java.version").startsWith("1.")) {
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/DetectorLoader.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/DetectorLoader.java
new file mode 100644
index 0000000..369c4b5
--- /dev/null
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/DetectorLoader.java
@@ -0,0 +1,35 @@
+package io.github.zekerzhayard.forgewrapper.installer.detector;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.ServiceLoader;
+
+public class DetectorLoader {
+    public static IFileDetector loadDetector() {
+        ServiceLoader<IFileDetector> sl = ServiceLoader.load(IFileDetector.class);
+        HashMap<String, IFileDetector> detectors = new HashMap<>();
+        for (IFileDetector detector : sl) {
+            detectors.put(detector.name(), detector);
+        }
+
+        boolean enabled = false;
+        IFileDetector temp = null;
+        for (Map.Entry<String, IFileDetector> detector : detectors.entrySet()) {
+            HashMap<String, IFileDetector> others = new HashMap<>(detectors);
+            others.remove(detector.getKey());
+            if (!enabled) {
+                enabled = detector.getValue().enabled(others);
+                if (enabled) {
+                    temp = detector.getValue();
+                }
+            } else if (detector.getValue().enabled(others)) {
+                throw new RuntimeException("There are two or more file detectors are enabled! (" + temp.toString() + ", " + detector.toString() + ")");
+            }
+        }
+
+        if (temp == null) {
+            throw new RuntimeException("No file detector is enabled!");
+        }
+        return temp;
+    }
+}
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/IFileDetector.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/IFileDetector.java
new file mode 100644
index 0000000..b816708
--- /dev/null
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/IFileDetector.java
@@ -0,0 +1,201 @@
+package io.github.zekerzhayard.forgewrapper.installer.detector;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.math.BigInteger;
+import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonNull;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import cpw.mods.modlauncher.Launcher;
+
+public interface IFileDetector {
+    /**
+     * @return The name of the detector.
+     */
+    String name();
+
+    /**
+     * If there are two or more detectors are enabled, an exception will be thrown. Removing anything from the map is in vain.
+     * @param others Other detectors.
+     * @return True represents enabled.
+     */
+    boolean enabled(HashMap<String, IFileDetector> others);
+
+    /**
+     * @return The ".minecraft/libraries" folder for normal. It can also be defined by JVM argument "-Dforgewrapper.librariesDir=&lt;libraries-path&gt;".
+     */
+    default Path getLibraryDir() {
+        String libraryDir = System.getProperty("forgewrapper.librariesDir");
+        if (libraryDir != null) {
+            return Paths.get(libraryDir).toAbsolutePath();
+        }
+        try {
+            Path launcher = Paths.get(Launcher.class.getProtectionDomain().getCodeSource().getLocation().toURI()).toAbsolutePath();
+            //              /<version>  /modlauncher/mods       /cpw        /libraries
+            return launcher.getParent().getParent().getParent().getParent().getParent().toAbsolutePath();
+        } catch (URISyntaxException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * @param forgeFullVersion Forge full version (e.g. 1.14.4-28.2.0).
+     * @return The forge installer jar path. It can also be defined by JVM argument "-Dforgewrapper.installer=&lt;installer-path&gt;".
+     */
+    default Path getInstallerJar(String forgeFullVersion) {
+        String installer = System.getProperty("forgewrapper.installer");
+        if (installer != null) {
+            return Paths.get(installer).toAbsolutePath();
+        }
+        return null;
+    }
+
+    /**
+     * @param mcVersion Minecraft version (e.g. 1.14.4).
+     * @return The minecraft client jar path. It can also be defined by JVM argument "-Dforgewrapper.minecraft=&lt;minecraft-path&gt;".
+     */
+    default Path getMinecraftJar(String mcVersion) {
+        String minecraft = System.getProperty("forgewrapper.minecraft");
+        if (minecraft != null) {
+            return Paths.get(minecraft).toAbsolutePath();
+        }
+        return null;
+    }
+
+    /**
+     * @param forgeFullVersion Forge full version (e.g. 1.14.4-28.2.0).
+     * @return The json object in the-installer-jar-->install_profile.json-->data-->xxx-->client.
+     */
+    default JsonObject getInstallProfileExtraData(String forgeFullVersion) {
+        Path installer = this.getInstallerJar(forgeFullVersion);
+        if (isFile(installer)) {
+            try (ZipFile zf = new ZipFile(installer.toFile())) {
+                ZipEntry ze = zf.getEntry("install_profile.json");
+                if (ze != null) {
+                    try (
+                        InputStream is = zf.getInputStream(ze);
+                        InputStreamReader isr = new InputStreamReader(is, StandardCharsets.UTF_8)
+                    ) {
+                        for (Map.Entry<String, JsonElement> entry : new JsonParser().parse(isr).getAsJsonObject().entrySet()) {
+                            if (entry.getKey().equals("data")) {
+                                return entry.getValue().getAsJsonObject();
+                            }
+                        }
+                    }
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        } else {
+            throw new RuntimeException("Can't detect the forge installer!");
+        }
+        return null;
+    }
+
+    /**
+     * Check all cached files.
+     * @param forgeFullVersion Forge full version (e.g. 1.14.4-28.2.0).
+     * @return True represents all files are ready.
+     */
+    default boolean checkExtraFiles(String forgeFullVersion) {
+        JsonObject jo = this.getInstallProfileExtraData(forgeFullVersion);
+        if (jo != null) {
+            Map<String, Path> libsMap = new HashMap<>();
+            Map<String, String> hashMap = new HashMap<>();
+
+            // Get all "data/<name>/client" elements.
+            for (Map.Entry<String, JsonElement> entry : jo.entrySet()) {
+                String clientStr = getElement(entry.getValue().getAsJsonObject(), "client").getAsString();
+                if (entry.getKey().endsWith("_SHA")) {
+                    Pattern p = Pattern.compile("^'(?<sha1>[A-Za-z0-9]{40})'$");
+                    Matcher m = p.matcher(clientStr);
+                    if (m.find()) {
+                        hashMap.put(entry.getKey(), m.group("sha1"));
+                    }
+                } else {
+                    Pattern p = Pattern.compile("^\\[(?<groupId>[^:]*):(?<artifactId>[^:]*):(?<version>[^:@]*)(:(?<prefix>[^@]*))?(@(?<type>[^]]*))?]$");
+                    Matcher m = p.matcher(clientStr);
+                    if (m.find()) {
+                        String groupId = nullToDefault(m.group("groupId"), "");
+                        String artifactId = nullToDefault(m.group("artifactId"), "");
+                        String version = nullToDefault(m.group("version"), "");
+                        String prefix = nullToDefault(m.group("prefix"), "");
+                        String type = nullToDefault(m.group("type"), "jar");
+                        libsMap.put(entry.getKey(), this.getLibraryDir()
+                            .resolve(groupId.replace('.', File.separatorChar))
+                            .resolve(artifactId)
+                            .resolve(version)
+                            .resolve(artifactId + "-" + version + (prefix.equals("") ? "" : "-") + prefix + "." + type).toAbsolutePath());
+                    }
+                }
+            }
+
+            // Check all cached libraries.
+            boolean checked = true;
+            for (Map.Entry<String, Path> entry : libsMap.entrySet()) {
+                checked = checked && this.checkExtraFile(entry.getValue(), hashMap.get(entry.getKey() + "_SHA"));
+            }
+            return checked;
+        }
+        // Skip installing process if installer profile doesn't exist.
+        return true;
+    }
+
+    /**
+     * Check the exact file.
+     * @param path The path of the file to check.
+     * @param sha1 The sha1 defined in installer.
+     * @return True represents the file is ready.
+     */
+    default boolean checkExtraFile(Path path, String sha1) {
+        return Files.isRegularFile(path) && (sha1 == null || sha1.equals("") || sha1.toLowerCase(Locale.ENGLISH).equals(getFileSHA1(path)));
+    }
+
+    static boolean isFile(Path path) {
+        return path != null && Files.isRegularFile(path);
+    }
+
+    static JsonElement getElement(JsonObject object, String property) {
+        Optional<Map.Entry<String, JsonElement>> first = object.entrySet().stream().filter(e -> e.getKey().equals(property)).findFirst();
+        if (first.isPresent()) {
+            return first.get().getValue();
+        }
+        return JsonNull.INSTANCE;
+    }
+
+    static String getFileSHA1(Path path) {
+        try {
+            StringBuilder sha1 = new StringBuilder(new BigInteger(1, MessageDigest.getInstance("SHA-1").digest(Files.readAllBytes(path))).toString(16));
+            while (sha1.length() < 40) {
+                sha1.insert(0, "0");
+            }
+            return sha1.toString().toLowerCase(Locale.ENGLISH);
+        } catch (IOException | NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    static String nullToDefault(String string, String defaultValue) {
+        return string == null ? defaultValue : string;
+    }
+}
diff --git a/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/MultiMCFileDetector.java b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/MultiMCFileDetector.java
new file mode 100644
index 0000000..cb87d27
--- /dev/null
+++ b/src/main/java/io/github/zekerzhayard/forgewrapper/installer/detector/MultiMCFileDetector.java
@@ -0,0 +1,46 @@
+package io.github.zekerzhayard.forgewrapper.installer.detector;
+
+import java.nio.file.Path;
+import java.util.HashMap;
+
+public class MultiMCFileDetector implements IFileDetector {
+    protected Path libraryDir = null;
+    protected Path installerJar = null;
+    protected Path minecraftJar = null;
+
+    @Override
+    public String name() {
+        return "MultiMC";
+    }
+
+    @Override
+    public boolean enabled(HashMap<String, IFileDetector> others) {
+        return others.size() == 0;
+    }
+
+    @Override
+    public Path getLibraryDir() {
+        if (this.libraryDir == null) {
+            this.libraryDir = IFileDetector.super.getLibraryDir();
+        }
+        return this.libraryDir;
+    }
+
+    @Override
+    public Path getInstallerJar(String forgeFullVersion) {
+        Path path = IFileDetector.super.getInstallerJar(forgeFullVersion);
+        if (path == null) {
+            return this.installerJar != null ? this.installerJar : (this.installerJar = this.getLibraryDir().resolve("net").resolve("minecraftforge").resolve("forge").resolve(forgeFullVersion).resolve("forge-" + forgeFullVersion + "-installer.jar").toAbsolutePath());
+        }
+        return path;
+    }
+
+    @Override
+    public Path getMinecraftJar(String mcVersion) {
+        Path path = IFileDetector.super.getMinecraftJar(mcVersion);
+        if (path == null) {
+            return this.minecraftJar != null ? this.minecraftJar : (this.minecraftJar = this.getLibraryDir().resolve("com").resolve("mojang").resolve("minecraft").resolve(mcVersion).resolve("minecraft-" + mcVersion + "-client.jar").toAbsolutePath());
+        }
+        return path;
+    }
+}
diff --git a/src/main/resources/META-INF/services/io.github.zekerzhayard.forgewrapper.installer.detector.IFileDetector b/src/main/resources/META-INF/services/io.github.zekerzhayard.forgewrapper.installer.detector.IFileDetector
new file mode 100644
index 0000000..44375f8
--- /dev/null
+++ b/src/main/resources/META-INF/services/io.github.zekerzhayard.forgewrapper.installer.detector.IFileDetector
@@ -0,0 +1 @@
+io.github.zekerzhayard.forgewrapper.installer.detector.MultiMCFileDetector
\ No newline at end of file