Avoid NPE on malformed/truncated failure stack traces (#1795)

Avoid NPE on malformed/truncated failure stack traces

Author: mjameswh

temporal-sdk/src/main/java/io/temporal/failure/DefaultFailureConverter.java

@@ -44,6 +44,7 @@
 import io.temporal.serviceclient.CheckedExceptionWrapper;
 import java.io.PrintWriter;
 import java.io.StringWriter;
+import java.util.ArrayList;
 import java.util.Optional;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -298,11 +299,14 @@ private StackTraceElement[] parseStackTrace(String stackTrace) {
     try {
       @SuppressWarnings("StringSplitter")
       String[] lines = stackTrace.split("\r\n|\n");
-      StackTraceElement[] result = new StackTraceElement[lines.length];
+      ArrayList<StackTraceElement> result = new ArrayList<>(lines.length);
       for (int i = 0; i < lines.length; i++) {
-        result[i] = parseStackTraceElement(lines[i]);
+        StackTraceElement elem = parseStackTraceElement(lines[i]);
+        if (elem != null) {
+          result.add(elem);
+        }
       }
-      return result;
+      return result.toArray(new StackTraceElement[result.size()]);
     } catch (Exception e) {
       if (log.isWarnEnabled()) {
         log.warn("Failed to parse stack trace: " + stackTrace);