1 files changed, 3 insertions, 1 deletions
diff --git a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
index 19b64dd3c1..d09dc5912e 100644
--- a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
+++ b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
@@ -43,7 +43,9 @@ import org.apache.poi.EmptyFileException;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.parallel.Isolated;
 
+@Isolated	// this test changes global static BYTE_ARRAY_MAX_OVERRIDE
 final class TestIOUtils {
     private static File TMP;
     private static final long LENGTH = 300 + new Random().nextInt(9000);
@@ -531,7 +533,7 @@ final class TestIOUtils {
         }
     }
 
-    public class NullInputStream extends InputStream {
+    public static class NullInputStream extends InputStream {
         private final int bytes;
         private final boolean exception;