Use ServiceLoader to load different implementations

compiler/frontend.java/src/META-INF/services/org.jetbrains.jet.lang.resolve.java.resolver.ProgressChecker

@@ -0,0 +1 @@
+org.jetbrains.jet.lang.resolve.java.resolver.ProgressCheckerImpl

compiler/frontend.java/src/META-INF/services/org.jetbrains.jet.lang.resolve.java.structure.JavaElementFactory

@@ -0,0 +1 @@
+org.jetbrains.jet.lang.resolve.java.structure.impl.JavaElementFactoryImpl

compiler/frontend.java/src/META-INF/services/org.jetbrains.jet.lang.resolve.java.structure.JavaSignatureFormatter

@@ -0,0 +1 @@
+org.jetbrains.jet.lang.resolve.java.structure.impl.JavaSignatureFormatterImpl

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/ProgressChecker.java

@@ -18,11 +18,21 @@ package org.jetbrains.jet.lang.resolve.java.resolver;
 
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Iterator;
+import java.util.ServiceLoader;
+
 public abstract class ProgressChecker {
+    private static ProgressChecker instance;
+
     @NotNull
     public static ProgressChecker getInstance() {
-        // TODO: ServiceLoader.load()
-        return new ProgressCheckerImpl();
+        if (instance == null) {
+            Iterator<ProgressChecker> iterator =
+                    ServiceLoader.load(ProgressChecker.class, ProgressChecker.class.getClassLoader()).iterator();
+            assert iterator.hasNext() : "No service found: " + ProgressChecker.class.getName();
+            instance = iterator.next();
+        }
+        return instance;
     }
 
     public abstract void checkCanceled();

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaElementFactory.java

@@ -17,13 +17,22 @@
 package org.jetbrains.jet.lang.resolve.java.structure;
 
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.jet.lang.resolve.java.structure.impl.JavaElementFactoryImpl;
+
+import java.util.Iterator;
+import java.util.ServiceLoader;
 
 public abstract class JavaElementFactory {
+    private static JavaElementFactory instance;
+
     @NotNull
     public static JavaElementFactory getInstance() {
-        // TODO: ServiceLoader.load
-        return new JavaElementFactoryImpl();
+        if (instance == null) {
+            Iterator<JavaElementFactory> iterator =
+                    ServiceLoader.load(JavaElementFactory.class, JavaElementFactory.class.getClassLoader()).iterator();
+            assert iterator.hasNext() : "No service found: " + JavaElementFactory.class.getName();
+            instance = iterator.next();
+        }
+        return instance;
     }
 
     @NotNull

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/structure/JavaSignatureFormatter.java

@@ -17,12 +17,22 @@
 package org.jetbrains.jet.lang.resolve.java.structure;
 
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.jet.lang.resolve.java.structure.impl.JavaSignatureFormatterImpl;
+
+import java.util.Iterator;
+import java.util.ServiceLoader;
 
 public abstract class JavaSignatureFormatter {
+    private static JavaSignatureFormatter instance;
+
+    @NotNull
     public static JavaSignatureFormatter getInstance() {
-        // TODO: ServiceLoader.load
-        return new JavaSignatureFormatterImpl();
+        if (instance == null) {
+            Iterator<JavaSignatureFormatter> iterator =
+                    ServiceLoader.load(JavaSignatureFormatter.class, JavaSignatureFormatter.class.getClassLoader()).iterator();
+            assert iterator.hasNext() : "No service found: " + JavaSignatureFormatter.class.getName();
+            instance = iterator.next();
+        }
+        return instance;
     }
 
     /**