1 files changed, 27 insertions, 14 deletions

diff --git a/src/main/java/org/junit/internal/requests/ClassRequest.java b/src/main/java/org/junit/internal/requests/ClassRequest.java
index 53bf520..3d6b100 100644
--- a/src/main/java/org/junit/internal/requests/ClassRequest.java
+++ b/src/main/java/org/junit/internal/requests/ClassRequest.java
@@ -1,26 +1,39 @@
 package org.junit.internal.requests;
 
-
 import org.junit.internal.builders.AllDefaultPossibilitiesBuilder;
 import org.junit.runner.Request;
 import org.junit.runner.Runner;
 
 public class ClassRequest extends Request {
-	private final Class<?> fTestClass;
+    private final Object runnerLock = new Object();
 
-	private boolean fCanUseSuiteMethod;
+    /*
+     * We have to use the f prefix, because IntelliJ's JUnit4IdeaTestRunner uses
+     * reflection to access this field. See
+     * https://github.com/junit-team/junit/issues/960
+     */
+    private final Class<?> fTestClass;
+    private final boolean canUseSuiteMethod;
+    private volatile Runner runner;
 
-	public ClassRequest(Class<?> testClass, boolean canUseSuiteMethod) {
-		fTestClass= testClass;
-		fCanUseSuiteMethod= canUseSuiteMethod;
-	}
+    public ClassRequest(Class<?> testClass, boolean canUseSuiteMethod) {
+        this.fTestClass = testClass;
+        this.canUseSuiteMethod = canUseSuiteMethod;
+    }
 
-	public ClassRequest(Class<?> testClass) {
-		this(testClass, true);
-	}
+    public ClassRequest(Class<?> testClass) {
+        this(testClass, true);
+    }
 
-	@Override
-	public Runner getRunner() {
-		return new AllDefaultPossibilitiesBuilder(fCanUseSuiteMethod).safeRunnerForClass(fTestClass);
-	}
+    @Override
+    public Runner getRunner() {
+        if (runner == null) {
+            synchronized (runnerLock) {
+                if (runner == null) {
+                    runner = new AllDefaultPossibilitiesBuilder(canUseSuiteMethod).safeRunnerForClass(fTestClass);
+                }
+            }
+        }
+        return runner;
+    }
 }
\ No newline at end of file