diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TBoolean.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TBoolean.java
index 20eaf08de..7f96bc5b6 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TBoolean.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TBoolean.java
@@ -88,6 +88,6 @@ public class TBoolean extends TObject implements TSerializable, TComparable<TBoo
     }
 
     public boolean getBoolean(TString key) {
-        return valueOf(TSystem.getProperty(key)).booleanValue();
+        return valueOf(TString.wrap(TSystem.getProperty(key.toString()))).booleanValue();
     }
 }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TInteger.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TInteger.java
index c0457291b..699fcab9a 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TInteger.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TInteger.java
@@ -172,7 +172,7 @@ public class TInteger extends TNumber implements TComparable<TInteger> {
     }
 
     public static TInteger getInteger(TString nm, TInteger val) {
-        TString result = TSystem.getProperty(nm);
+        TString result = TString.wrap(TSystem.getProperty(nm.toString()));
         return result != null ? TInteger.valueOf(result) : val;
     }
 
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
index c40ab282a..0f66dad19 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
@@ -225,7 +225,7 @@ public class TLong extends TNumber implements TComparable<TLong> {
     }
 
     public static TLong getLong(TString nm, TLong val) {
-        TString result = TSystem.getProperty(nm);
+        TString result = TString.wrap(TSystem.getProperty(nm.toString()));
         return result != null ? TLong.valueOf(result) : val;
     }
 
diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java
index 8ad18df67..743f8e371 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java
@@ -15,6 +15,8 @@
  */
 package org.teavm.classlib.java.lang;
 
+import java.util.Enumeration;
+import java.util.Properties;
 import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.classlib.java.io.TConsole;
 import org.teavm.classlib.java.io.TInputStream;
@@ -34,6 +36,7 @@ public final class TSystem extends TObject {
     public static final TPrintStream out = new TPrintStream(new TConsoleOutputStreamStdout(), false);
     public static final TPrintStream err = new TPrintStream(new TConsoleOutputStreamStderr(), false);
     public static final TInputStream in = new TConsoleInputStream();
+    private static Properties properties;
 
     private TSystem() {
     }
@@ -109,16 +112,60 @@ public final class TSystem extends TObject {
     @Import(name = "currentTimeMillis", module = "runtime")
     private static native double currentTimeMillisImpl();
 
-    public static TString getProperty(@SuppressWarnings("unused") TString key) {
-        // TODO: make implementation
-        return null;
+    private static void initPropertiesIfNeeded() {
+        if (properties == null) {
+            Properties defaults = new Properties();
+            defaults.put("java.version", "1.8");
+            defaults.put("os.name", "TeaVM");
+            defaults.put("file.separator", "/");
+            defaults.put("path.separator", ":");
+            defaults.put("line.separator", lineSeparator());
+            properties = new Properties(defaults);
+        }
     }
 
-    public static TString getProperty(TString key, TString def) {
-        TString value = getProperty(key);
+    public static String getProperty(@SuppressWarnings("unused") String key) {
+        initPropertiesIfNeeded();
+        return properties.getProperty(key);
+    }
+
+    public static String getProperty(String key, String def) {
+        String value = getProperty(key);
         return value != null ? value : def;
     }
 
+    public static Properties getProperties() {
+        initPropertiesIfNeeded();
+        Properties result = new Properties();
+        copyProperties(properties, result);
+        return result;
+    }
+
+    public static void setProperties(Properties props) {
+        initPropertiesIfNeeded();
+        copyProperties(props, properties);
+    }
+
+    private static void copyProperties(Properties from, Properties to) {
+        to.clear();
+        if (from != null) {
+            Enumeration<?> e = from.propertyNames();
+            while (e.hasMoreElements()) {
+                String key = (String) e.nextElement();
+                to.setProperty(key, from.getProperty(key));
+            }
+        }
+    }
+
+    public static String setProperty(String key, String value) {
+        initPropertiesIfNeeded();
+        return (String) properties.put(key, value);
+    }
+
+    public static String clearProperty(String key) {
+        return (String) properties.remove(key);
+    }
+
     @GeneratedBy(SystemNativeGenerator.class)
     @PluggableDependency(SystemNativeGenerator.class)
     public static native void setErr(TPrintStream err);
@@ -148,7 +195,7 @@ public final class TSystem extends TObject {
         return ((TObject) x).identity();
     }
 
-    public static TString lineSeparator() {
-        return TString.wrap("\n");
+    public static String lineSeparator() {
+        return "\n";
     }
 }
diff --git a/tests/src/test/java/org/teavm/classlib/java/lang/SystemTest.java b/tests/src/test/java/org/teavm/classlib/java/lang/SystemTest.java
index d7ea62ad1..339fe8aa4 100644
--- a/tests/src/test/java/org/teavm/classlib/java/lang/SystemTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/lang/SystemTest.java
@@ -16,13 +16,16 @@
 package org.teavm.classlib.java.lang;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.fail;
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
+import java.util.Properties;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.teavm.junit.SkipJVM;
 import org.teavm.junit.TeaVMTestRunner;
 
 @RunWith(TeaVMTestRunner.class)
@@ -125,4 +128,25 @@ public class SystemTest {
         assertEquals("err overridden\n", new String(err.toByteArray()));
         assertEquals("out overridden\n", new String(out.toByteArray()));
     }
+
+    @Test
+    @SkipJVM
+    public void propertiesWork() {
+        Properties properties = System.getProperties();
+        assertNotNull(properties);
+        assertNotNull(properties.getProperty("java.version"));
+
+        System.setProperty("myprop", "foo");
+        assertNull(properties.getProperty("foo"));
+        assertEquals("foo", System.getProperty("myprop"));
+        properties = System.getProperties();
+        assertEquals("foo", properties.getProperty("myprop"));
+
+        Properties newProps = new Properties();
+        newProps.setProperty("myprop2", "bar");
+        System.setProperties(newProps);
+        assertNotNull(System.getProperty("java.version"));
+        assertNull(System.getProperty("myprop"));
+        assertEquals("bar", System.getProperty("myprop2"));
+    }
 }