diff --git a/classlib/src/main/java/org/teavm/classlib/java/net/TURLDecoder.java b/classlib/src/main/java/org/teavm/classlib/java/net/TURLDecoder.java
new file mode 100644
index 000000000..0ef12adfa
--- /dev/null
+++ b/classlib/src/main/java/org/teavm/classlib/java/net/TURLDecoder.java
@@ -0,0 +1,107 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.teavm.classlib.java.net;
+
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.IllegalCharsetNameException;
+import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnsupportedCharsetException;
+import java.util.Objects;
+
+public final class TURLDecoder {
+    private TURLDecoder() {
+    }
+
+    @Deprecated
+    public static String decode(String s) {
+        return decode(s, StandardCharsets.UTF_8);
+    }
+
+    public static String decode(String s, String enc) throws UnsupportedEncodingException {
+        Objects.requireNonNull(enc);
+
+        if (enc.isEmpty()) {
+            throw new UnsupportedEncodingException("Invalid parameter: enc");
+        }
+
+        if (s.indexOf('%') == -1) {
+            if (s.indexOf('+') == -1) {
+                return s;
+            }
+            char[] str = s.toCharArray();
+            for (int i = 0; i < str.length; i++) {
+                if (str[i] == '+') {
+                    str[i] = ' ';
+                }
+            }
+            return new String(str);
+        }
+
+        Charset charset = null;
+        try {
+            charset = Charset.forName(enc);
+        } catch (IllegalCharsetNameException | UnsupportedCharsetException e) {
+            UnsupportedEncodingException toThrow = new UnsupportedEncodingException();
+            toThrow.initCause(e);
+            throw toThrow;
+        }
+
+        return decode(s, charset);
+    }
+
+    private static String decode(String s, Charset charset) {
+        char[] strBuf = new char[s.length()];
+        byte[] buf = new byte[s.length() / 3];
+        int bufLen = 0;
+
+        for (int i = 0; i < s.length();) {
+            char c = s.charAt(i);
+            if (c == '+') {
+                strBuf[bufLen] = ' ';
+            } else if (c == '%') {
+                int len = 0;
+                do {
+                    if (i + 2 >= s.length()) {
+                        throw new IllegalArgumentException("Incomplete % sequence at: " + i);
+                    }
+                    int d1 = Character.digit(s.charAt(i + 1), 16);
+                    int d2 = Character.digit(s.charAt(i + 2), 16);
+                    if (d1 == -1 || d2 == -1) {
+                        throw new IllegalArgumentException("Invalid % sequence (" +  s.substring(i, i + 3)
+                                + ") at " + i);
+                    }
+                    buf[len++] = (byte) ((d1 << 4) + d2);
+                    i += 3;
+                } while (i < s.length() && s.charAt(i) == '%');
+
+                CharBuffer cb = charset.decode(ByteBuffer.wrap(buf, 0, len));
+                len = cb.length();
+                System.arraycopy(cb.array(), 0, strBuf, bufLen, len);
+                bufLen += len;
+                continue;
+            } else {
+                strBuf[bufLen] = c;
+            }
+            i++;
+            bufLen++;
+        }
+        return new String(strBuf, 0, bufLen);
+    }
+}
diff --git a/classlib/src/main/java/org/teavm/classlib/java/net/TURLEncoder.java b/classlib/src/main/java/org/teavm/classlib/java/net/TURLEncoder.java
new file mode 100644
index 000000000..a1d552398
--- /dev/null
+++ b/classlib/src/main/java/org/teavm/classlib/java/net/TURLEncoder.java
@@ -0,0 +1,102 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.teavm.classlib.java.net;
+
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.charset.UnsupportedCharsetException;
+import java.util.Objects;
+
+public final class TURLEncoder {
+
+    static final String digits = "0123456789ABCDEF";
+
+    private TURLEncoder() {
+    }
+
+    @Deprecated
+    public static String encode(String s) {
+        // Guess a bit bigger for encoded form
+        StringBuilder buf = new StringBuilder(s.length() + 16);
+        for (int i = 0; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            if (ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z'
+                    || ch >= '0' && ch <= '9' || ".-*_".indexOf(ch) > -1) {
+                buf.append(ch);
+            } else if (ch == ' ') {
+                buf.append('+');
+            } else {
+                byte[] bytes = new String(new char[] { ch }).getBytes(StandardCharsets.UTF_8);
+                for (byte b : bytes) {
+                    buf.append('%');
+                    buf.append(digits.charAt((b & 0xf0) >> 4));
+                    buf.append(digits.charAt(b & 0xf));
+                }
+            }
+        }
+        return buf.toString();
+    }
+
+    public static String encode(String s, String enc) throws UnsupportedEncodingException {
+        Objects.requireNonNull(s);
+        Objects.requireNonNull(enc);
+
+        // check for UnsupportedEncodingException
+        try {
+            Charset.forName(enc);
+        } catch (UnsupportedCharsetException e) {
+            throw new UnsupportedEncodingException(enc);
+        }
+
+        // Guess a bit bigger for encoded form
+        StringBuffer buf = new StringBuffer(s.length() + 16);
+        int start = -1;
+        for (int i = 0; i < s.length(); i++) {
+            char ch = s.charAt(i);
+            if (ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z'
+                    || ch >= '0' && ch <= '9' || " .-*_".indexOf(ch) > -1) {
+                if (start >= 0) {
+                    convert(s.substring(start, i), buf, enc);
+                    start = -1;
+                }
+                if (ch != ' ') {
+                    buf.append(ch);
+                } else {
+                    buf.append('+');
+                }
+            } else {
+                if (start < 0) {
+                    start = i;
+                }
+            }
+        }
+        if (start >= 0) {
+            convert(s.substring(start), buf, enc);
+        }
+        return buf.toString();
+    }
+
+    private static void convert(String s, StringBuffer buf, String enc) throws UnsupportedEncodingException {
+        byte[] bytes = s.getBytes(enc);
+        for (int j = 0; j < bytes.length; j++) {
+            buf.append('%');
+            buf.append(digits.charAt((bytes[j] & 0xf0) >> 4));
+            buf.append(digits.charAt(bytes[j] & 0xf));
+        }
+    }
+}
diff --git a/tests/src/test/java/org/teavm/classlib/java/net/URLDecoderTest.java b/tests/src/test/java/org/teavm/classlib/java/net/URLDecoderTest.java
new file mode 100644
index 000000000..a5c489eeb
--- /dev/null
+++ b/tests/src/test/java/org/teavm/classlib/java/net/URLDecoderTest.java
@@ -0,0 +1,59 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.teavm.classlib.java.net;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.teavm.junit.TeaVMTestRunner;
+
+@RunWith(TeaVMTestRunner.class)
+public class URLDecoderTest {
+
+    @Test
+    public void test_Constructor() {
+        URLDecoder ud = new URLDecoder();
+        assertNotNull("Constructor failed.", ud);
+    }
+
+    @Test
+    public void test_decodeLjava_lang_String() {
+        final String url = "http://localhost.";
+        final String url2 = "telnet://justWantToHaveFun.com:400";
+        final String url3 = "file://myServer.org/a file with spaces.jpg";
+        assertTrue("1. Incorrect encoding/decoding", URLDecoder.decode(URLEncoder.encode(url)).equals(url));
+        assertTrue("2. Incorrect encoding/decoding", URLDecoder.decode(URLEncoder.encode(url2)).equals(url2));
+        assertTrue("3. Incorrect encoding/decoding", URLDecoder.decode(URLEncoder.encode(url3)).equals(url3));
+    }
+
+    @Test
+    public void test_decodeLjava_lang_String_Ljava_lang_String() {
+        // Regression for HARMONY-467
+        try {
+            URLDecoder.decode("", "");
+            fail("UnsupportedEncodingException expected");
+        } catch (UnsupportedEncodingException e) {
+            // Expected
+        }
+    }
+}
diff --git a/tests/src/test/java/org/teavm/classlib/java/net/URLEncoderTest.java b/tests/src/test/java/org/teavm/classlib/java/net/URLEncoderTest.java
new file mode 100644
index 000000000..7bf0bd11d
--- /dev/null
+++ b/tests/src/test/java/org/teavm/classlib/java/net/URLEncoderTest.java
@@ -0,0 +1,63 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.teavm.classlib.java.net;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.teavm.junit.TeaVMTestRunner;
+
+@RunWith(TeaVMTestRunner.class)
+public class URLEncoderTest {
+
+    @Test
+    @SuppressWarnings("deprecation")
+    public void test_encodeLjava_lang_String() {
+        final String url = "http://localhost.";
+        final String url2 = "telnet://justWantToHaveFun.com:400";
+        final String url3 = "file://myServer.org/a file with spaces.jpg";
+
+        assertEquals("1. Incorrect encoding/decoding", url, URLDecoder.decode(URLEncoder.encode(url)));
+        assertEquals("2. Incorrect encoding/decoding", url2, URLDecoder.decode(URLEncoder.encode(url2)));
+        assertEquals("3. Incorrect encoding/decoding", url3, URLDecoder.decode(URLEncoder.encode(url3)));
+    }
+
+    @Test
+    public void test_encodeLjava_lang_StringLjava_lang_String()
+            throws Exception {
+        // Regression for HARMONY-24
+        try {
+            URLEncoder.encode("str", "unknown_enc");
+            fail("Assert 0: Should throw UEE for invalid encoding");
+        } catch (UnsupportedEncodingException e) {
+            // expected
+        }
+
+        // Regression for HARMONY-1233
+        try {
+            URLEncoder.encode(null, "harmony");
+            fail("NullPointerException expected");
+        } catch (NullPointerException e) {
+            // expected
+        }
+    }
+}