diff --git a/rust-launcher/Cargo.toml b/rust-launcher/Cargo.toml
index 61ee308..58bc763 100644
--- a/rust-launcher/Cargo.toml
+++ b/rust-launcher/Cargo.toml
@@ -2,7 +2,3 @@
 name = "launcher"
 version = "1.8.0"
 authors = ["https://icedtea.classpath.org/wiki/IcedTea-Web"]
-
-[dependencies]
-[target.'cfg(windows)'.dependencies]
-dunce = "0.1.1"
diff --git a/rust-launcher/src/dirs_paths_helper.rs b/rust-launcher/src/dirs_paths_helper.rs
index a83011d..c0faa79 100644
--- a/rust-launcher/src/dirs_paths_helper.rs
+++ b/rust-launcher/src/dirs_paths_helper.rs
@@ -1,12 +1,10 @@
 use os_access;
+use dunce;
 
 use std;
 use std::io;
 use std::env;
 
-#[cfg(windows)] extern crate dunce;
-
-
 pub static ICEDTEA_WEB: &'static str = "icedtea-web";
 pub static DEPLOYMENT_PROPERTIES: &'static str = "deployment.properties";
 
diff --git a/rust-launcher/src/dunce.rs b/rust-launcher/src/dunce.rs
new file mode 100644
index 0000000..68b4249
--- /dev/null
+++ b/rust-launcher/src/dunce.rs
@@ -0,0 +1,315 @@
+//! Filesystem paths in Windows are a total mess. This crate normalizes paths to the most
+//! compatible (but still correct) format, so that you don't have to worry about the mess.
+//!
+//! In Windows the regular/legacy paths (`C:\foo`) are supported by all programs, but have
+//! lots of bizarre restrictions for backwards compatibility with MS-DOS.
+//!
+//! And there are Windows NT UNC paths (`\\?\C:\foo`), which are more robust and with fewer
+//! gotchas, but are rarely supported by Windows programs. Even Microsoft's own!
+//!
+//! This crate converts paths to legacy format whenever possible, but leaves UNC paths as-is
+//! when they can't be unambiguously expressed in a simpler way. This allows legacy programs
+//! to access all paths they can possibly access, and UNC-aware programs to access all paths.
+//!
+//! On non-Windows platforms these functions leave paths unmodified, so it's safe to use them
+//! unconditionally for all platforms.
+//!
+//! Parsing is based on https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
+//!
+//! [Project homepage](https://crates.rs/crates/dunce).
+#![doc(html_logo_url = "https://assets.gitlab-static.net/uploads/-/system/project/avatar/4717715/dyc.png")]
+
+#[cfg(any(windows, test))]
+use std::ffi::OsStr;
+use std::fs;
+use std::io;
+#[cfg(windows)]
+use std::os::windows::ffi::OsStrExt;
+#[cfg(windows)]
+use std::path::{Component, Prefix};
+use std::path::{Path, PathBuf};
+
+/// Takes any path, and when possible, converts Windows UNC paths to regular paths.
+///
+/// On non-Windows this is no-op.
+///
+/// `\\?\C:\Windows` will be converted to `C:\Windows`,
+/// but `\\?\C:\COM` will be left as-is (due to a reserved filename).
+///
+/// Use this to pass arbitrary paths to programs that may not be UNC-aware.
+/// It's generally safe to pass UNC paths to legacy programs, because
+/// the paths contain a reserved character, so will gracefully fail
+/// if used with wrong APIs.
+///
+/// This function does not perform any I/O.
+///
+/// Currently paths with unpaired surrogates aren't converted even if they
+/// can be due to limitations of Rust's `OsStr` API.
+pub fn simplified(path: &Path) -> &Path {
+    if is_safe_to_strip_unc(path) {
+        // unfortunately we can't safely strip prefix from a non-Unicode path
+        path.to_str().and_then(|s| s.get(4..)).map(Path::new).unwrap_or(path)
+    } else {
+        path
+    }
+}
+
+/// Like `std::fs::canonicalize()`, but on Windows it outputs the most
+/// compatible form of a path instead of UNC.
+#[cfg(windows)]
+pub fn canonicalize<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
+    let real_path = fs::canonicalize(path)?;
+    Ok(if is_safe_to_strip_unc(&real_path) {
+        real_path.to_str().and_then(|s| s.get(4..)).map(PathBuf::from).unwrap_or(real_path)
+    } else {
+        real_path
+    })
+}
+
+/// Like `std::fs::canonicalize()`, but on Windows it outputs the most
+/// compatible form of a path instead of UNC.
+#[cfg(not(windows))]
+#[inline]
+pub fn canonicalize<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
+    fs::canonicalize(path)
+}
+
+pub use self::canonicalize as realpath;
+
+#[cfg(any(windows,test))]
+fn windows_char_len(s: &OsStr) -> usize {
+    #[cfg(unix)]
+    let len = s.to_string_lossy().chars().map(|c| if c as u32 <= 0xFFFF {1} else {2}).sum();
+    #[cfg(windows)]
+    let len = s.encode_wide().count();
+    len
+}
+
+#[cfg(any(windows,test))]
+fn is_valid_filename<P: AsRef<OsStr>>(file_name: P) -> bool {
+    let file_name = file_name.as_ref();
+    if windows_char_len(file_name) > 255 {
+        return false;
+    }
+
+    // Non-unicode is safe, but Rust can't reasonably losslessly operate on such strings
+    let file_name = if let Some(s) = file_name.to_str() {
+        s
+    } else {
+        return false;
+    };
+    if file_name.is_empty() {
+        return false;
+    }
+    // Only ASCII subset is checked, and UTF-8 is safe for that
+    let byte_str = file_name.as_bytes();
+    for &c in byte_str {
+        match c {
+            0..=31 |
+            b'<' | b'>' | b':' | b'"' |
+            b'/' | b'\\' | b'|' | b'?' | b'*' => return false,
+            _ => {},
+        }
+    }
+
+    // Filename can't end with . or space (except before extension, but this checks the whole name)
+    let last_char = byte_str[byte_str.len()-1];
+    if last_char == b' ' || last_char == b'.' {
+        return false;
+    }
+    true
+}
+
+#[cfg(any(windows, test))]
+const RESERVED_NAMES: [&'static str; 22] = [
+    "AUX", "NUL", "PRN", "CON", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8",
+    "COM9", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
+];
+
+#[cfg(any(windows, test))]
+fn is_reserved<P: AsRef<OsStr>>(file_name: P) -> bool {
+    // con.txt is reserved too
+    if let Some(stem) = Path::new(&file_name).file_stem() {
+        // all reserved DOS names have ASCII-compatible stem
+        if let Some(name) = stem.to_str() {
+            // "con.. .txt" is "CON" for DOS
+            let trimmed = right_trim(name);
+            if trimmed.len() <= 4 {
+                for name in &RESERVED_NAMES {
+                    if name.eq_ignore_ascii_case(trimmed) {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+    false
+}
+
+#[cfg(not(windows))]
+fn is_safe_to_strip_unc(_path: &Path) -> bool {
+    false
+}
+
+#[cfg(windows)]
+fn is_safe_to_strip_unc(path: &Path) -> bool {
+    let mut components = path.components();
+    match components.next() {
+        Some(Component::Prefix(p)) => match p.kind() {
+            Prefix::VerbatimDisk(..) => {},
+            _ => return false, // Other kinds of UNC paths
+        },
+        _ => return false, // relative or empty
+    }
+
+    for component in components {
+        match component {
+            Component::RootDir => {},
+            Component::Normal(file_name) => {
+                // it doesn't allocate in most cases,
+                // and checks are interested only in the ASCII subset, so lossy is fine
+                if !is_valid_filename(file_name) || is_reserved(file_name) {
+                    return false;
+                }
+            }
+            _ => return false, // UNC paths take things like ".." literally
+        };
+    }
+
+    if windows_char_len(path.as_os_str()) > 260 { // However, if the path is going to be used as a directory it's 248
+        return false;
+    }
+    true
+}
+
+/// Trim '.' and ' '
+#[cfg(any(windows, test))]
+fn right_trim(mut s: &str) -> &str {
+    while s.len() > 0 {
+        let last = s.len()-1;
+        unsafe {
+            if s.as_bytes()[last] == b'.' || s.as_bytes()[last] == b' ' {
+                s = s.get_unchecked(0..last) // trim of ASCII byte can't break UTF-8
+            } else {
+                break;
+            }
+        }
+    }
+    s
+}
+
+#[test]
+fn trim_test() {
+    assert_eq!("a", right_trim("a."));
+    assert_eq!("ą", right_trim("ą."));
+    assert_eq!("a", right_trim("a "));
+    assert_eq!("ąą", right_trim("ąą "));
+    assert_eq!("a", right_trim("a. . . ....   "));
+    assert_eq!("a. . . ..ź", right_trim("a. . . ..ź..   "));
+    assert_eq!(" b", right_trim(" b"));
+    assert_eq!(" べ", right_trim(" べ"));
+    assert_eq!("c. c", right_trim("c. c."));
+    assert_eq!("。", right_trim("。"));
+    assert_eq!("", right_trim(""));
+}
+
+#[test]
+fn reserved() {
+    assert!(is_reserved("CON"));
+    assert!(is_reserved("con"));
+    assert!(is_reserved("con.con"));
+    assert!(is_reserved("COM4"));
+    assert!(is_reserved("COM4.txt"));
+    assert!(is_reserved("COM4 .txt"));
+    assert!(is_reserved("con."));
+    assert!(is_reserved("con ."));
+    assert!(is_reserved("con  "));
+    assert!(is_reserved("con . "));
+    assert!(is_reserved("con . .txt"));
+    assert!(is_reserved("con.....txt"));
+    assert!(is_reserved("PrN....."));
+
+    assert!(!is_reserved(" PrN....."));
+    assert!(!is_reserved(" CON"));
+    assert!(!is_reserved("COM0"));
+    assert!(!is_reserved("COM77"));
+    assert!(!is_reserved(" CON "));
+    assert!(!is_reserved(".CON"));
+    assert!(!is_reserved("@CON"));
+    assert!(!is_reserved("not.CON"));
+    assert!(!is_reserved("CON。"));
+}
+
+#[test]
+fn len() {
+    assert_eq!(1, windows_char_len(OsStr::new("a")));
+    assert_eq!(1, windows_char_len(OsStr::new("€")));
+    assert_eq!(1, windows_char_len(OsStr::new("本")));
+    assert_eq!(2, windows_char_len(OsStr::new("🧐")));
+    assert_eq!(2, windows_char_len(OsStr::new("®®")));
+}
+
+#[test]
+fn valid() {
+    assert!(!is_valid_filename(".."));
+    assert!(!is_valid_filename("."));
+    assert!(!is_valid_filename("aaaaaaaaaa:"));
+    assert!(!is_valid_filename("ą:ą"));
+    assert!(!is_valid_filename(""));
+    assert!(!is_valid_filename("a "));
+    assert!(!is_valid_filename(" a. "));
+    assert!(!is_valid_filename("a/"));
+    assert!(!is_valid_filename("/a"));
+    assert!(!is_valid_filename("/"));
+    assert!(!is_valid_filename("\\"));
+    assert!(!is_valid_filename("\\a"));
+    assert!(!is_valid_filename("<x>"));
+    assert!(!is_valid_filename("a*"));
+    assert!(!is_valid_filename("?x"));
+    assert!(!is_valid_filename("a\0a"));
+    assert!(!is_valid_filename("\x1f"));
+    assert!(!is_valid_filename(::std::iter::repeat("a").take(257).collect::<String>()));
+
+    assert!(is_valid_filename(::std::iter::repeat("®").take(254).collect::<String>()));
+    assert!(is_valid_filename("ファイル"));
+    assert!(is_valid_filename("a"));
+    assert!(is_valid_filename("a.aaaaaaaa"));
+    assert!(is_valid_filename("a........a"));
+    assert!(is_valid_filename("       b"));
+}
+
+#[test]
+#[cfg(windows)]
+fn realpath_test() {
+    assert_eq!(r"C:\WINDOWS", canonicalize(r"C:\Windows").unwrap().to_str().unwrap().to_uppercase());
+    assert_ne!(r".", canonicalize(r".").unwrap().to_str().unwrap());
+}
+
+#[test]
+#[cfg(windows)]
+fn strip() {
+    assert_eq!(Path::new(r"C:\foo\😀"), simplified(Path::new(r"\\?\C:\foo\😀")));
+    assert_eq!(Path::new(r"\\?\serv\"), simplified(Path::new(r"\\?\serv\")));
+    assert_eq!(Path::new(r"\\.\C:\notdisk"), simplified(Path::new(r"\\.\C:\notdisk")));
+}
+
+#[test]
+#[cfg(windows)]
+fn safe() {
+    assert!(is_safe_to_strip_unc(Path::new(r"\\?\C:\foo\bar")));
+    assert!(is_safe_to_strip_unc(Path::new(r"\\?\Z:\foo\bar\")));
+    assert!(is_safe_to_strip_unc(Path::new(r"\\?\Z:\😀\🎃\")));
+    assert!(is_safe_to_strip_unc(Path::new(r"\\?\c:\foo")));
+
+    let long = ::std::iter::repeat("®").take(160).collect::<String>();
+    assert!(is_safe_to_strip_unc(Path::new(&format!(r"\\?\c:\{}", long))));
+    assert!(!is_safe_to_strip_unc(Path::new(&format!(r"\\?\c:\{}\{}", long, long))));
+
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\C:\foo\.\bar")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\C:\foo\..\bar")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\c\foo")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\c\foo/bar")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\c:foo")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\cc:foo")));
+    assert!(!is_safe_to_strip_unc(Path::new(r"\\?\c:foo\bar")));
+}
diff --git a/rust-launcher/src/main.rs b/rust-launcher/src/main.rs
index d13e1a6..0d9fb80 100644
--- a/rust-launcher/src/main.rs
+++ b/rust-launcher/src/main.rs
@@ -9,6 +9,7 @@ mod utils;
 mod property;
 mod jars_helper;
 mod log_helper;
+mod dunce;
 
 use std::string::String;
 use std::fmt::Write;
