Updated cache logic to be exception-safe.

src/io/nayuki/fastqrcodegen/QrTemplate.java

@@ -57,13 +57,18 @@ final class QrTemplate {
 			}
 		}
 		
+		try {
 			QrTemplate tpl = new QrTemplate(version);
 			synchronized(cache) {
 				cache[version] = new SoftReference<>(tpl);
+			}
+			return tpl;
+		} finally {
+			synchronized(cache) {
 				isPending[version] = false;
 				cache.notifyAll();
 			}
-		return tpl;
+		}
 	}
 	
 	

src/io/nayuki/fastqrcodegen/ReedSolomonGenerator.java

@@ -59,13 +59,18 @@ final class ReedSolomonGenerator {
 			}
 		}
 		
+		try {
 			ReedSolomonGenerator rs = new ReedSolomonGenerator(degree);
 			synchronized(cache) {
 				cache[degree] = new SoftReference<>(rs);
+			}
+			return rs;
+		} finally {
+			synchronized(cache) {
 				isPending[degree] = false;
 				cache.notifyAll();
 			}
-		return rs;
+		}
 	}