fix(newinstance): forces usage of the newest version of the class

src/main/java/spoon/support/reflect/declaration/CtClassImpl.java

@@ -16,14 +16,6 @@
  */
 package spoon.support.reflect.declaration;
 
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
-import java.util.Set;
-
 import spoon.SpoonException;
 import spoon.SpoonModelBuilder.InputType;
 import spoon.reflect.code.CtCodeElement;
@@ -44,6 +36,16 @@
 import spoon.support.reflect.eval.VisitorPartialEvaluator;
 import spoon.support.util.SignatureBasedSortedSet;
 
+import java.io.File;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+
 /**
  * The implementation for {@link spoon.reflect.declaration.CtClass}.
  *
@@ -251,10 +253,25 @@ public T newInstance() {
 		try {
 			JDTBasedSpoonCompiler spooner = new JDTBasedSpoonCompiler(getFactory());
 			spooner.compile(InputType.CTTYPES); // compiling the types of the factory
-			Class<?> klass = new URLClassLoader(new URL[] { spooner.getBinaryOutputDirectory().toURL() }).loadClass(getQualifiedName());
+			Class<?> klass = new NewInstanceClassloader(spooner.getBinaryOutputDirectory()).loadClass(getQualifiedName());
 			return (T) klass.newInstance();
 		} catch (Exception e) {
 			throw new SpoonException(e);
 		}
 	}
+
+	private class NewInstanceClassloader extends URLClassLoader {
+		NewInstanceClassloader(File binaryOutputDirectory) throws MalformedURLException {
+			super(new URL[] { binaryOutputDirectory.toURL()});
+		}
+
+		@Override
+		public Class<?> loadClass(String s) throws ClassNotFoundException {
+			try {
+				return findClass(s);
+			} catch (Exception e) {
+				return super.loadClass(s);
+			}
+		}
+	}
 }

src/test/java/spoon/test/compilation/CompilationTest.java

@@ -1,19 +1,8 @@
 package spoon.test.compilation;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
-import java.io.File;
-import java.lang.reflect.Method;
-import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
-import java.util.List;
-
 import org.eclipse.jdt.internal.compiler.batch.CompilationUnit;
 import org.junit.Assert;
 import org.junit.Test;
-
 import spoon.Launcher;
 import spoon.compiler.SpoonCompiler;
 import spoon.reflect.code.BinaryOperatorKind;
@@ -30,6 +19,20 @@
 import spoon.reflect.visitor.filter.TypeFilter;
 import spoon.support.compiler.jdt.FileCompiler;
 import spoon.support.compiler.jdt.JDTBasedSpoonCompiler;
+import spoon.test.compilation.testclasses.Bar;
+import spoon.test.compilation.testclasses.IBar;
+import spoon.testing.utils.ModelUtils;
+
+import java.io.File;
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class CompilationTest {
 
@@ -106,6 +109,31 @@ public void compileTest() throws Exception {
 		Assert.assertEquals(42, m.invoke(aClass.newInstance()));
 	}
 
+	@Test
+	public void testNewInstanceFromExistingClass() throws Exception {
+		CtClass<Bar> barCtType = (CtClass<Bar>) ModelUtils.buildClass(Bar.class);
+		CtReturn<Integer> m = barCtType.getMethod("m").getBody().getStatement(0);
+		// we cannot use Bar because it causes a runtime cast exception (2 different Bar from different classloader)
+		IBar bar = barCtType.newInstance();
+		int value = bar.m();
+		assertEquals(1, value);
+
+		// change the return value
+		m.setReturnedExpression(m.getFactory().Code().createLiteral(2));
+
+		bar = barCtType.newInstance();
+		value = bar.m();
+		assertEquals(2, value);
+
+		m.replace(m.getFactory().Code().createCodeSnippetStatement("throw new FooEx()"));
+		try {
+			bar = barCtType.newInstance();
+			value = bar.m();
+			fail();
+		} catch (Exception ignore) {}
+
+	}
+
 	@Test
 	public void testNewInstance() throws Exception {
 		// contract: a ctclass can be instantiated, and each modification results in a new valid object

src/test/java/spoon/test/compilation/testclasses/Bar.java

@@ -0,0 +1,11 @@
+package spoon.test.compilation.testclasses;
+
+public class Bar implements IBar {
+
+	@Override
+	public int m() {
+		return 1;
+	}
+}
+
+class FooEx extends RuntimeException {}

src/test/java/spoon/test/compilation/testclasses/IBar.java

@@ -0,0 +1,8 @@
+package spoon.test.compilation.testclasses;
+
+/**
+ * Created by thomas on 28/10/16.
+ */
+public interface IBar {
+	int m();
+}