Found Potential Fix for javapathfinder#429

Seems like there needs to be model classes in the file and charset packages for java.nio. These are as small as I could make them

src/classes/modules/java.base/java/nio/charset/Charset.java

@@ -0,0 +1,72 @@
+package java.nio.charset;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+
+public class Charset {
+    private static final String DEFAULT_CHARSET_NAME = "UTF-8";
+    private static final Map<String, Charset> charsetMap = new HashMap<>();
+    private final String name;
+
+    // Static initialization to ensure default charset always exists
+    static {
+        Charset defaultCharset = new Charset(DEFAULT_CHARSET_NAME);
+        charsetMap.put(DEFAULT_CHARSET_NAME.toLowerCase(), defaultCharset);
+        charsetMap.put("default", defaultCharset);
+    }
+
+    protected Charset(String canonicalName) {
+        if (canonicalName == null) {
+            throw new IllegalArgumentException("Charset name cannot be null");
+        }
+        this.name = canonicalName;
+    }
+
+    public static Charset defaultCharset() {
+        return charsetMap.get(DEFAULT_CHARSET_NAME.toLowerCase());
+    }
+
+    public static Charset forName(String charsetName) {
+        if (charsetName == null) {
+            throw new IllegalArgumentException("Null charset name");
+        }
+
+        String normalizedName = charsetName.toLowerCase();
+
+        // Always return the default charset if the requested one isn't found
+        // This simplifies the model while preventing null charset issues
+        return charsetMap.getOrDefault(normalizedName, defaultCharset());
+    }
+
+    public final String name() {
+        return name;
+    }
+
+    // Simple encode/decode stubs that don't actually do encoding
+    // but prevent null pointer issues
+    public CharBuffer decode(ByteBuffer bb) {
+        if (bb == null) {
+            throw new IllegalArgumentException("ByteBuffer cannot be null");
+        }
+        // Simplified implementation that just copies bytes to chars
+        char[] chars = new char[bb.remaining()];
+        for (int i = 0; i < chars.length; i++) {
+            chars[i] = (char) (bb.get() & 0xFF);
+        }
+        return CharBuffer.wrap(new String(chars));
+    }
+
+    public ByteBuffer encode(CharBuffer cb) {
+        if (cb == null) {
+            throw new IllegalArgumentException("CharBuffer cannot be null");
+        }
+        // Simplified implementation that just copies chars to bytes
+        byte[] bytes = new byte[cb.remaining()];
+        for (int i = 0; i < bytes.length; i++) {
+            bytes[i] = (byte) cb.get();
+        }
+        return ByteBuffer.wrap(bytes);
+    }
+}

src/classes/modules/java.base/java/nio/files/FileSystem.java

@@ -0,0 +1,11 @@
+package java.nio.file;
+
+import java.nio.file.spi.FileSystemProvider;
+
+public abstract class FileSystem {
+    protected FileSystem() {}
+
+    public abstract Path getPath(String first, String... more);
+
+    public abstract FileSystemProvider provider();
+}

src/classes/modules/java.base/java/nio/files/FileSystems.java

@@ -0,0 +1,186 @@
+package java.nio.file;
+
+import java.nio.file.spi.FileSystemProvider;
+import java.net.URI;
+import java.util.Map;
+import java.util.HashMap;
+
+public class FileSystems {
+    private static volatile FileSystem defaultFileSystem;
+
+    static {
+        defaultFileSystem = new FileSystem() {
+            private final FileSystemProvider provider = new FileSystemProvider() {
+                @Override
+                public FileSystem newFileSystem(URI uri, Map<String, ?> env) {
+                    return this.getFileSystem();
+                }
+
+                @Override
+                public String getScheme() {
+                    return "file";
+                }
+
+                @Override
+                public FileSystem getFileSystem() {
+                    return defaultFileSystem;
+                }
+            };
+
+            @Override
+            public Path getPath(String first, String... more) {
+                return new Path() {
+                    private final String path;
+                    private final String[] segments;
+
+                    {
+                        StringBuilder sb = new StringBuilder(first);
+                        if (more != null) {
+                            for (String s : more) {
+                                if (s != null && !s.isEmpty()) {
+                                    if (sb.length() > 0 && sb.charAt(sb.length() - 1) != '/') {
+                                        sb.append('/');
+                                    }
+                                    sb.append(s);
+                                }
+                            }
+                        }
+                        path = sb.toString();
+                        segments = path.split("/");
+                    }
+
+                    @Override
+                    public FileSystem getFileSystem() {
+                        return defaultFileSystem;
+                    }
+
+                    @Override
+                    public boolean isAbsolute() {
+                        return path.startsWith("/");
+                    }
+
+                    @Override
+                    public Path getRoot() {
+                        return isAbsolute() ? getFileSystem().getPath("/") : null;
+                    }
+
+                    @Override
+                    public Path getFileName() {
+                        if (path.isEmpty()) return null;
+                        return getFileSystem().getPath(segments[segments.length - 1]);
+                    }
+
+                    @Override
+                    public Path getParent() {
+                        int lastSep = path.lastIndexOf('/');
+                        return lastSep > 0 ? getFileSystem().getPath(path.substring(0, lastSep)) : null;
+                    }
+
+                    @Override
+                    public int getNameCount() {
+                        if (path.isEmpty()) return 0;
+                        if (path.equals("/")) return 0;
+                        int count = segments.length;
+                        if (path.startsWith("/")) count--;
+                        if (path.endsWith("/")) count--;
+                        return count;
+                    }
+
+                    @Override
+                    public Path getName(int index) {
+                        if (index < 0 || index >= getNameCount()) {
+                            throw new IllegalArgumentException();
+                        }
+                        return getFileSystem().getPath(segments[path.startsWith("/") ? index + 1 : index]);
+                    }
+
+                    @Override
+                    public Path subpath(int beginIndex, int endIndex) {
+                        if (beginIndex < 0 || beginIndex >= getNameCount() ||
+                            endIndex > getNameCount() || beginIndex >= endIndex) {
+                            throw new IllegalArgumentException();
+                        }
+
+                        StringBuilder result = new StringBuilder();
+                        int start = path.startsWith("/") ? beginIndex + 1 : beginIndex;
+                        for (int i = start; i < start + (endIndex - beginIndex); i++) {
+                            if (result.length() > 0) result.append('/');
+                            result.append(segments[i]);
+                        }
+                        return getFileSystem().getPath(result.toString());
+                    }
+
+                    @Override
+                    public boolean startsWith(Path other) {
+                        return path.startsWith(other.toString());
+                    }
+
+                    @Override
+                    public boolean endsWith(Path other) {
+                        return path.endsWith(other.toString());
+                    }
+
+                    @Override
+                    public Path normalize() {
+                        return this; // Simplified implementation
+                    }
+
+                    @Override
+                    public Path resolve(Path other) {
+                        return getFileSystem().getPath(path + "/" + other.toString());
+                    }
+
+                    @Override
+                    public Path relativize(Path other) {
+                        return other; // Simplified implementation
+                    }
+
+                    @Override
+                    public URI toUri() {
+                        try {
+                            return new URI("file", null, path, null);
+                        } catch (Exception e) {
+                            return null;
+                        }
+                    }
+
+                    @Override
+                    public Path toAbsolutePath() {
+                        if (isAbsolute()) return this;
+                        return getFileSystem().getPath("/" + path);
+                    }
+
+                    @Override
+                    public Path toRealPath(LinkOption... options) {
+                        return toAbsolutePath();
+                    }
+
+                    @Override
+                    public String toString() {
+                        return path;
+                    }
+
+                    @Override
+                    public int compareTo(Path other) {
+                        return path.compareTo(other.toString());
+                    }
+                };
+            }
+
+            @Override
+            public FileSystemProvider provider() {
+                return provider;
+            }
+        };
+    }
+
+    public static FileSystem getDefault() {
+        return defaultFileSystem;
+    }
+
+    public static FileSystem newFileSystem(URI uri, Map<String, ?> env, ClassLoader loader) {
+        if (uri == null)
+            throw new NullPointerException();
+        return defaultFileSystem;
+    }
+}

src/classes/modules/java.base/java/nio/files/FileVisitOption.java

@@ -0,0 +1,5 @@
+package java.nio.file;
+
+public enum FileVisitOption {
+    FOLLOW_LINKS
+}

src/classes/modules/java.base/java/nio/files/Files.java

@@ -0,0 +1,50 @@
+package java.nio.file;
+
+import java.nio.file.attribute.*;
+import java.nio.file.spi.FileSystemProvider;
+import java.util.Set;
+import java.util.stream.Stream;
+import java.io.IOException;
+
+public class Files {
+    private Files() {}
+
+    public static FileSystem getFileSystem(Path path) {
+        return path.getFileSystem();
+    }
+
+    public static FileSystemProvider provider(Path path) {
+        return path.getFileSystem().provider();
+    }
+
+    public static <A extends BasicFileAttributes> A readAttributes(
+            Path path, Class<A> type, LinkOption... options) throws IOException {
+        return (A) new BasicFileAttributes() {
+            public FileTime lastModifiedTime() { return FileTime.fromMillis(System.currentTimeMillis()); }
+            public FileTime lastAccessTime() { return FileTime.fromMillis(System.currentTimeMillis()); }
+            public FileTime creationTime() { return FileTime.fromMillis(System.currentTimeMillis()); }
+            public boolean isRegularFile() { return true; }
+            public boolean isDirectory() { return false; }
+            public boolean isSymbolicLink() { return false; }
+            public boolean isOther() { return false; }
+            public long size() { return 0L; }
+            public Object fileKey() { return null; }
+        };
+    }
+
+    public static Stream<Path> walk(Path start, FileVisitOption... options) throws IOException {
+        return Stream.of(start);
+    }
+
+    public static Stream<Path> walk(Path start, int maxDepth, FileVisitOption... options) throws IOException {
+        return Stream.of(start);
+    }
+
+    public static boolean exists(Path path) throws IOException {
+        try {
+             return Files.exists(path);
+        } catch (IOException e) {
+             return false;
+        }
+    }
+}

src/classes/modules/java.base/java/nio/files/Path.java

@@ -0,0 +1,25 @@
+package java.nio.file;
+import java.net.URI;
+
+public interface Path extends Comparable<Path> {
+    FileSystem getFileSystem();
+    boolean isAbsolute();
+    Path getRoot();
+    Path getFileName();
+    Path getParent();
+    int getNameCount();
+    Path getName(int index);
+    Path subpath(int beginIndex, int endIndex);
+    boolean startsWith(Path other);
+    boolean endsWith(Path other);
+    Path normalize();
+    Path resolve(Path other);
+    Path relativize(Path other);
+    URI toUri();
+    Path toAbsolutePath();
+    Path toRealPath(LinkOption... options);
+
+    static Path of(String first, String... more) {
+        return FileSystems.getDefault().getPath(first, more);
+    }
+}

src/classes/modules/java.base/java/nio/files/attribute/BasicFileAttributes.java

@@ -0,0 +1,13 @@
+package java.nio.file.attribute;
+
+public interface BasicFileAttributes {
+    FileTime lastModifiedTime();
+    FileTime lastAccessTime();
+    FileTime creationTime();
+    boolean isRegularFile();
+    boolean isDirectory();
+    boolean isSymbolicLink();
+    boolean isOther();
+    long size();
+    Object fileKey();
+}

src/classes/modules/java.base/java/nio/files/attribute/FileTime.java

@@ -0,0 +1,17 @@
+package java.nio.file.attribute;
+
+public final class FileTime {
+    private final long time;
+
+    private FileTime(long time) {
+        this.time = time;
+    }
+
+    public static FileTime fromMillis(long time) {
+        return new FileTime(time);
+    }
+
+    public long toMillis() {
+        return time;
+    }
+}