diff --git a/classpath/java-io.cpp b/classpath/java-io.cpp
index a91067a3da..da95bb068a 100644
--- a/classpath/java-io.cpp
+++ b/classpath/java-io.cpp
@@ -163,6 +163,21 @@ Java_java_io_File_delete(JNIEnv* e, jclass, jstring path)
   return r == 0;
 }
 
+extern "C" JNIEXPORT jboolean JNICALL
+Java_java_io_File_isDirectory(JNIEnv* e, jclass, jstring path)
+{
+  const char* chars = e->GetStringUTFChars(path, 0);
+  if (chars) {
+    STRUCT_STAT s;
+    int r = STAT(chars, &s);
+    bool v = (r == 0 and S_ISDIR(s.st_mode));
+    e->ReleaseStringUTFChars(path, chars);
+    return v;
+  } else {
+    return false;
+  }
+}
+
 extern "C" JNIEXPORT jboolean JNICALL
 Java_java_io_File_exists(JNIEnv* e, jclass, jstring path)
 {
diff --git a/classpath/java/io/File.java b/classpath/java/io/File.java
index 8dd379c205..d99b2fa628 100644
--- a/classpath/java/io/File.java
+++ b/classpath/java/io/File.java
@@ -23,6 +23,12 @@ public class File {
     this(parent.getPath() + FileSeparator + child);
   }
 
+  private static native boolean isDirectory(String path);
+
+  public boolean isDirectory() {
+    return isDirectory(path);
+  }
+
   public String getName() {
     int index = path.lastIndexOf(FileSeparator);
     if (index >= 0) {
diff --git a/classpath/java/lang/Byte.java b/classpath/java/lang/Byte.java
index 1d1f4caac2..8863b67547 100644
--- a/classpath/java/lang/Byte.java
+++ b/classpath/java/lang/Byte.java
@@ -37,6 +37,10 @@ public final class Byte extends Number implements Comparable<Byte> {
     return toString(v, 10);
   }
 
+  public static byte parseByte(String s) {
+    return (byte) Integer.parseInt(s);
+  }
+
   public byte byteValue() {
     return value;
   }
diff --git a/classpath/java/lang/Runtime.java b/classpath/java/lang/Runtime.java
index ddc657ec87..3546e388c2 100644
--- a/classpath/java/lang/Runtime.java
+++ b/classpath/java/lang/Runtime.java
@@ -60,6 +60,8 @@ public class Runtime {
 
   public native long freeMemory();
 
+  public native long totalMemory();
+
   private static class MyProcess extends Process {
     private int pid;
     private final int in;
diff --git a/src/builtin.cpp b/src/builtin.cpp
index 11d645527b..a7d3801059 100644
--- a/src/builtin.cpp
+++ b/src/builtin.cpp
@@ -561,6 +561,13 @@ Java_java_lang_Runtime_freeMemory(Thread*, jobject)
   return 0;
 }
 
+extern "C" JNIEXPORT jlong JNICALL
+Java_java_lang_Runtime_totalMemory(Thread*, jobject)
+{
+  // todo
+  return 0;
+}
+
 extern "C" JNIEXPORT jobject JNICALL
 Java_java_lang_Throwable_trace(Thread* t, jclass, jint skipCount)
 {