impossible cast in spi/db/TypeInfo.java

[LanceAndersen]

Previously tracked via: https://bugs.openjdk.java.net/browse/JDK-8182558

My colleagues Marsela Sulku and Maria Sam are working on detecting errors with new errorprone checks and have found one impossible cast in openjdk:

Method jaxws/src/java.xml.ws/share/classes/com/sun/xml/internal/ws/spi/db/TypeInfo.java#getItemType contains
if (type instanceof Class && ((Class)type).isArray() && !byte[].class.equals(type)) {
Type componentType = ((Class)type).getComponentType();
Type genericComponentType = null;
if (genericType!= null && genericType instanceof GenericArrayType) {
GenericArrayType arrayType = (GenericArrayType) type;
genericComponentType = arrayType.getGenericComponentType();
componentType = arrayType.getGenericComponentType();
}

The cast to (GenericArrayType) cannot succeed because type is already a Class. (Probably this code has never worked or been tested)

It's very likely that this is a typo for:

--- a/src/java.xml.ws/share/classes/com/sun/xml/internal/ws/spi/db/TypeInfo.java
+++ b/src/java.xml.ws/share/classes/com/sun/xml/internal/ws/spi/db/TypeInfo.java
@@ -177,7 +177,7 @@
Type componentType = ((Class)type).getComponentType();
Type genericComponentType = null;
if (genericType!= null && genericType instanceof GenericArrayType) {

• GenericArrayType arrayType = (GenericArrayType) type;

• GenericArrayType arrayType = (GenericArrayType) genericType;
  genericComponentType = arrayType.getGenericComponentType();
  componentType = arrayType.getGenericComponentType();
  }