Lwm2m Fix bug create new Device with X509 Trust / update credential to X509 trust

common/data/src/main/java/org/thingsboard/server/common/data/StringUtils.java

@@ -21,7 +21,15 @@ public class StringUtils {
         return source == null || source.isEmpty();
     }
 
+    public static boolean isBlank(String source) {
+        return source == null || source.isEmpty() || source.trim().isEmpty();
+    }
+
     public static boolean isNotEmpty(String source) {
         return source != null && !source.isEmpty();
     }
+
+    public static boolean isNotBlank(String source) {
+        return source != null && !source.isEmpty() && !source.trim().isEmpty();
+    }
 }

dao/src/main/java/org/thingsboard/server/dao/device/DeviceCredentialsServiceImpl.java

@@ -183,7 +183,7 @@ public class DeviceCredentialsServiceImpl extends AbstractEntityService implemen
                 break;
             case X509:
                 X509ClientCredentials x509Config = (X509ClientCredentials) clientCredentials;
-                if (x509Config.getCert() != null) {
+                if ((StringUtils.isNotBlank(x509Config.getCert()))) {
                     String cert = EncryptionUtil.trimNewLines(x509Config.getCert());
                     String sha3Hash = EncryptionUtil.getSha3Hash(cert);
                     x509Config.setCert(cert);
@@ -272,7 +272,7 @@ public class DeviceCredentialsServiceImpl extends AbstractEntityService implemen
                 break;
             case X509:
                 X509ClientCredentials x509CCredentials = (X509ClientCredentials) clientCredentials;
-                if (x509CCredentials.getCert() != null) {
+                if (StringUtils.isNotBlank(x509CCredentials.getCert())) {
                     try {
                         SecurityUtil.certificate.decode(Base64.decodeBase64(x509CCredentials.getCert()));
                     } catch (Exception e) {