diff --git a/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotExtension.groovy b/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotExtension.groovy
index eba9305..dc2a4ad 100644
--- a/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotExtension.groovy
+++ b/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotExtension.groovy
@@ -4,9 +4,12 @@ import au.com.origin.snapshots.SnapshotVerifier
 import au.com.origin.snapshots.config.PropertyResolvingSnapshotConfig
 import au.com.origin.snapshots.config.SnapshotConfig
 import au.com.origin.snapshots.config.SnapshotConfigInjector
+import groovy.transform.CompileStatic
 import org.spockframework.runtime.extension.AbstractAnnotationDrivenExtension
+import org.spockframework.runtime.model.FeatureInfo
 import org.spockframework.runtime.model.SpecInfo
 
+@CompileStatic
 class SnapshotExtension extends AbstractAnnotationDrivenExtension<EnableSnapshots> implements SnapshotConfigInjector {
 
 	SnapshotVerifier snapshotVerifier;
@@ -17,7 +20,9 @@ class SnapshotExtension extends AbstractAnnotationDrivenExtension<EnableSnapshot
 
 	void visitSpec(SpecInfo spec) {
 		def snapshotMethodInterceptor = new SnapshotMethodInterceptor(snapshotVerifier)
-		spec.allFeatures.featureMethod*.addInterceptor(snapshotMethodInterceptor)
+		for (FeatureInfo feature : spec.allFeatures) {
+			feature.featureMethod.addInterceptor(snapshotMethodInterceptor)
+		}
 		spec.addCleanupSpecInterceptor(snapshotMethodInterceptor)
 	}
 
@@ -25,4 +30,4 @@ class SnapshotExtension extends AbstractAnnotationDrivenExtension<EnableSnapshot
 	SnapshotConfig getSnapshotConfig() {
 		return new PropertyResolvingSnapshotConfig()
 	}
-}
\ No newline at end of file
+}
diff --git a/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotMethodInterceptor.groovy b/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotMethodInterceptor.groovy
index 0f6b789..579da7a 100644
--- a/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotMethodInterceptor.groovy
+++ b/java-snapshot-testing-spock/src/main/groovy/au/com/origin/snapshots/spock/SnapshotMethodInterceptor.groovy
@@ -4,14 +4,18 @@ import au.com.origin.snapshots.Expect
 import au.com.origin.snapshots.SnapshotVerifier
 import au.com.origin.snapshots.logging.LoggingHelper
 import au.com.origin.snapshots.utils.ReflectionUtils
+import groovy.transform.CompileStatic
+import java.lang.reflect.Field
 import java.lang.reflect.Method
+import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import org.spockframework.runtime.extension.AbstractMethodInterceptor
 import org.spockframework.runtime.extension.IMethodInvocation
 
 // Based on this issue: https://github.com/spockframework/spock/issues/652
+@CompileStatic
 class SnapshotMethodInterceptor extends AbstractMethodInterceptor {
-	private log = LoggerFactory.getLogger( SnapshotMethodInterceptor.class )
+	private final Logger log = LoggerFactory.getLogger( SnapshotMethodInterceptor.class )
 	private final SnapshotVerifier snapshotVerifier;
 
 	SnapshotMethodInterceptor(SnapshotVerifier snapshotVerifier) {
@@ -28,8 +32,9 @@ class SnapshotMethodInterceptor extends AbstractMethodInterceptor {
 			System.arraycopy invocation.arguments, 0, newArguments, 0, invocation.arguments.length
 			invocation.arguments = newArguments
 		}
-		invocation.method.reflection.parameterTypes.eachWithIndex { type, i ->
-			if (Expect.class == type) {
+		def parameterTypes = invocation.method.reflection.parameterTypes
+		for (int i = 0; i < parameterTypes.length; i++) {
+			if (Expect.class == parameterTypes[i]) {
 				LoggingHelper.deprecatedV5(log, "Injecting 'Expect' via method a argument is no longer recommended. Consider using instance variable injection instead.")
 				invocation.arguments[i] = new Expect(snapshotVerifier, invocation.feature.featureMethod.reflection)
 			}
@@ -38,8 +43,8 @@ class SnapshotMethodInterceptor extends AbstractMethodInterceptor {
 	}
 
 	private void updateInstanceVariable(Object testInstance, Method testMethod) {
-		ReflectionUtils.findFieldByPredicate(testInstance.class, { field -> field.getType() == Expect.class })
-		.ifPresent({ field ->
+		ReflectionUtils.findFieldByPredicate(testInstance.class, { Field field -> field.getType() == Expect.class })
+		.ifPresent({ Field field ->
 			Expect expect = Expect.of(snapshotVerifier, testMethod);
 			ReflectionUtils.makeAccessible(field);
 			try {
diff --git a/java-snapshot-testing-spock/src/test/groovy/au/com/origin/snapshots/spock/GroovyRuntimeCompatibilitySpec.groovy b/java-snapshot-testing-spock/src/test/groovy/au/com/origin/snapshots/spock/GroovyRuntimeCompatibilitySpec.groovy
new file mode 100644
index 0000000..9a15a98
--- /dev/null
+++ b/java-snapshot-testing-spock/src/test/groovy/au/com/origin/snapshots/spock/GroovyRuntimeCompatibilitySpec.groovy
@@ -0,0 +1,23 @@
+package au.com.origin.snapshots.spock
+
+import spock.lang.Specification
+
+class GroovyRuntimeCompatibilitySpec extends Specification {
+
+	private static final String REMOVED_IN_GROOVY_6 = 'org/codehaus/groovy/runtime/callsite/CallSiteArray'
+
+	def "extension classes do not reference the call site cache that Groovy 6 removed"() {
+		given:
+		def classesRoot = new File(SnapshotExtension.protectionDomain.codeSource.location.toURI())
+		def extensionClasses = []
+		classesRoot.eachFileRecurse { file ->
+			if (file.name.endsWith('.class')) {
+				extensionClasses << file
+			}
+		}
+
+		expect:
+		!extensionClasses.empty
+		extensionClasses.findAll { new String(it.bytes, 'ISO-8859-1').contains(REMOVED_IN_GROOVY_6) }.empty
+	}
+}