diff --git a/make/test/BuildTestLib.gmk b/make/test/BuildTestLib.gmk
index b9f03209df4..f1574988b6f 100644
--- a/make/test/BuildTestLib.gmk
+++ b/make/test/BuildTestLib.gmk
@@ -36,7 +36,7 @@ TEST_LIB_SUPPORT := $(SUPPORT_OUTPUTDIR)/test/lib
 
 $(eval $(call SetupJavaCompilation, BUILD_WB_JAR, \
     TARGET_RELEASE := $(TARGET_RELEASE_NEWJDK_UPGRADED), \
-    SRC := $(TEST_LIB_SOURCE_DIR)/jdk/test/whitebox/parser, \
+    SRC := $(TEST_LIB_SOURCE_DIR)/jdk/test/whitebox/, \
     BIN := $(TEST_LIB_SUPPORT)/wb_classes, \
     JAR := $(TEST_LIB_SUPPORT)/wb.jar, \
     DISABLED_WARNINGS := deprecation removal preview, \
@@ -53,7 +53,13 @@ $(eval $(call SetupJavaCompilation, BUILD_TEST_LIB_JAR, \
     HEADERS := $(TEST_LIB_SUPPORT)/test-lib_headers, \
     JAR := $(TEST_LIB_SUPPORT)/test-lib.jar, \
     DISABLED_WARNINGS := try deprecation rawtypes unchecked serial cast removal preview, \
-    JAVAC_FLAGS := --enable-preview, \
+    JAVAC_FLAGS := --add-exports java.base/sun.security.util=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.classfile=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.classfile.attribute=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.classfile.constantpool=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.classfile.java.lang.constant=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.module=ALL-UNNAMED \
+        --enable-preview, \
 ))
 
 TARGETS += $(BUILD_TEST_LIB_JAR)
diff --git a/test/lib/jdk/test/lib/net/HttpHeaderParser.java b/test/lib/jdk/test/lib/net/HttpHeaderParser.java
index 71b3a84fdaa..86e45fcd4de 100644
--- a/test/lib/jdk/test/lib/net/HttpHeaderParser.java
+++ b/test/lib/jdk/test/lib/net/HttpHeaderParser.java
@@ -34,7 +34,7 @@ import java.util.Map;
 
 import static java.util.Objects.requireNonNull;
 
-public class HttpHeaderParser {
+public final class HttpHeaderParser {
     private static final char CR = '\r';
     private static final char LF = '\n';
     private static final char HT = '\t';