diff --git a/org.eclipse.jdt.debug.tests/java9/LogicalStructures.java b/org.eclipse.jdt.debug.tests/java9/LogicalStructures.java
index 1244ca8..cb3ad4b 100644
--- a/org.eclipse.jdt.debug.tests/java9/LogicalStructures.java
+++ b/org.eclipse.jdt.debug.tests/java9/LogicalStructures.java
@@ -44,7 +44,7 @@
 				System.gc();
 				garbage = Arrays.asList(new String("a"), new String("b"), new String("c"));
 			}
-		}, 50, 20);
+		}, 200, 20);
 	}
 
 }
diff --git a/org.eclipse.jdt.debug.tests/testprograms/LogicalStructures.java b/org.eclipse.jdt.debug.tests/testprograms/LogicalStructures.java
index 1244ca8..cb3ad4b 100644
--- a/org.eclipse.jdt.debug.tests/testprograms/LogicalStructures.java
+++ b/org.eclipse.jdt.debug.tests/testprograms/LogicalStructures.java
@@ -44,7 +44,7 @@
 				System.gc();
 				garbage = Arrays.asList(new String("a"), new String("b"), new String("c"));
 			}
-		}, 50, 20);
+		}, 200, 20);
 	}
 
 }
diff --git a/org.eclipse.jdt.debug.tests/tests/org/eclipse/jdt/debug/tests/variables/TestLogicalStructures.java b/org.eclipse.jdt.debug.tests/tests/org/eclipse/jdt/debug/tests/variables/TestLogicalStructures.java
index 1d0f49b..d125b71 100644
--- a/org.eclipse.jdt.debug.tests/tests/org/eclipse/jdt/debug/tests/variables/TestLogicalStructures.java
+++ b/org.eclipse.jdt.debug.tests/tests/org/eclipse/jdt/debug/tests/variables/TestLogicalStructures.java
@@ -66,7 +66,7 @@
 			assertEquals("Should be one logical structure type", 1, types.length);
 
 			IJavaObject logicalValue = (IJavaObject) types[0].getLogicalStructure(value);
-			Thread.sleep(200); // run a few GC cycles
+			Thread.sleep(500); // run a few GC cycles
 			assertEquals("Logical value should be an array", "java.lang.Object[]", logicalValue.getJavaType().getName());
 
 			IJavaArray array = (IJavaArray) logicalValue;
@@ -105,7 +105,7 @@
 			assertEquals("Should be one logical structure type", 1, types.length);
 
 			IJavaObject logicalValue = (IJavaObject) types[0].getLogicalStructure(value);
-			Thread.sleep(200); // run a few GC cycles
+			Thread.sleep(500); // run a few GC cycles
 			assertEquals("Logical value should be an array", "java.lang.Object[]", logicalValue.getJavaType().getName());
 
 			IJavaArray array = (IJavaArray) logicalValue;
@@ -144,7 +144,7 @@
 			assertEquals("Should be one logical structure type", 1, types.length);
 
 			IJavaObject logicalValue = (IJavaObject) types[0].getLogicalStructure(value);
-			Thread.sleep(200); // run a few GC cycles
+			Thread.sleep(500); // run a few GC cycles
 			IVariable[] children = logicalValue.getVariables();
 			assertEquals("Should be two elements in the structure", 2, children.length);
 			assertEquals("First entry should be key", "key", children[0].getName());