diff --git a/org.jacoco.ant.test/src/org/jacoco/ant/CoverageTaskTest.xml b/org.jacoco.ant.test/src/org/jacoco/ant/CoverageTaskTest.xml
index de7cb09970..01c3689ad6 100644
--- a/org.jacoco.ant.test/src/org/jacoco/ant/CoverageTaskTest.xml
+++ b/org.jacoco.ant.test/src/org/jacoco/ant/CoverageTaskTest.xml
@@ -152,7 +152,7 @@
 		<au:assertFileExists file="${exec.file}"/>
 		<au:assertLogContains text="Target executed"/>
 
-		<java classname="org.jacoco.ant.DumpExecClassNames" classpath="${java.class.path}" failonerror="true">
+		<java classname="org.jacoco.ant.DumpExecClassNames" fork="true" classpath="${java.class.path}" failonerror="true">
 			<arg value="${exec.file}" />
 		</java>
 		<au:assertLogContains text="java/sql/Timestamp"/>
diff --git a/org.jacoco.ant.test/src/org/jacoco/ant/ReportTaskTest.xml b/org.jacoco.ant.test/src/org/jacoco/ant/ReportTaskTest.xml
index 0481c21825..2ffa9694be 100644
--- a/org.jacoco.ant.test/src/org/jacoco/ant/ReportTaskTest.xml
+++ b/org.jacoco.ant.test/src/org/jacoco/ant/ReportTaskTest.xml
@@ -71,7 +71,7 @@
 	</target>
 
 	<target name="testReportWithSourceButNoDebug">
-		<java classname="org.jacoco.ant.RemoveDebugInfos" classpath="${java.class.path}" failonerror="true">
+		<java classname="org.jacoco.ant.RemoveDebugInfos" fork="true" classpath="${java.class.path}" failonerror="true">
 			<arg value="${org.jacoco.ant.reportTaskTest.classes.dir}/org/jacoco/ant/TestTarget.class" />
 			<arg value="${temp.dir}/TestTarget.class" />
 		</java>
@@ -89,7 +89,7 @@
 	</target>
 
 	<target name="testReportWithSourceDirButNoDebug">
-		<java classname="org.jacoco.ant.RemoveDebugInfos" classpath="${java.class.path}" failonerror="true">
+		<java classname="org.jacoco.ant.RemoveDebugInfos" fork="true" classpath="${java.class.path}" failonerror="true">
 			<arg value="${org.jacoco.ant.reportTaskTest.classes.dir}/org/jacoco/ant/TestTarget.class" />
 			<arg value="${temp.dir}/TestTarget.class" />
 		</java>