Minor improvements and better test cases.

(cherry picked from commit 08282ea09d)

imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/ByteArrayImageInputStreamSpi.java

@@ -35,7 +35,6 @@ import com.twelvemonkeys.imageio.spi.ProviderInfo;
 import javax.imageio.spi.ImageInputStreamSpi;
 import javax.imageio.stream.ImageInputStream;
 import java.io.File;
-import java.io.IOException;
 import java.util.Locale;
 
 /**
@@ -56,7 +55,7 @@ public class ByteArrayImageInputStreamSpi extends ImageInputStreamSpi {
         super(providerInfo.getVendorName(), providerInfo.getVersion(), byte[].class);
     }
 
-    public ImageInputStream createInputStreamInstance(Object pInput, boolean pUseCache, File pCacheDir) throws IOException {
+    public ImageInputStream createInputStreamInstance(Object pInput, boolean pUseCache, File pCacheDir) {
         if (pInput instanceof byte[]) {
             return new ByteArrayImageInputStream((byte[]) pInput);
         }

imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/stream/URLImageInputStreamSpi.java

@@ -114,6 +114,11 @@ public class URLImageInputStreamSpi extends ImageInputStreamSpi {
         }
     }
 
+    @Override
+    public boolean canUseCacheFile() {
+        return true;
+    }
+
     public String getDescription(final Locale pLocale) {
         return "Service provider that instantiates an ImageInputStream from a URL";
     }