From d4b35cb445985c7dd552fcfd3526e8d25b5f9ae0 Mon Sep 17 00:00:00 2001
From: rob bygrave <robin.bygrave@gmail.com>
Date: Fri, 13 Dec 2019 13:35:54 +1300
Subject: [PATCH] #1889 - NPE at Str.java:16) when using
 DB.sqlUpdate(...).addBatch() without any bind parameters

---
 .../java/io/ebeaninternal/server/lib/Str.java  | 10 ++++++++--
 .../batchinsert/TestBatchInsertSimple.java     | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/main/java/io/ebeaninternal/server/lib/Str.java b/src/main/java/io/ebeaninternal/server/lib/Str.java
index 2980331ec..02b3d9e37 100644
--- a/src/main/java/io/ebeaninternal/server/lib/Str.java
+++ b/src/main/java/io/ebeaninternal/server/lib/Str.java
@@ -13,14 +13,20 @@ public class Str {
   public static String add(String s0, String s1, String... args) {
 
     // determine a decent buffer size
-    int len = 16 + s0.length() + s1.length();
+    int len = 16 + s0.length();
+    if (s1 != null) {
+      len += s1.length();
+    }
     for (String arg1 : args) {
       len += (arg1 == null) ? 0 : arg1.length();
     }
 
     // append all the strings into the buffer
     StringBuilder sb = new StringBuilder(len);
-    sb.append(s0).append(s1);
+    sb.append(s0);
+    if (s1 != null) {
+      sb.append(s1);
+    }
     for (String arg : args) {
       if (arg != null) {
         sb.append(arg);
diff --git a/src/test/java/org/tests/batchinsert/TestBatchInsertSimple.java b/src/test/java/org/tests/batchinsert/TestBatchInsertSimple.java
index a98f21c0e..0f3c20332 100644
--- a/src/test/java/org/tests/batchinsert/TestBatchInsertSimple.java
+++ b/src/test/java/org/tests/batchinsert/TestBatchInsertSimple.java
@@ -1,6 +1,7 @@
 package org.tests.batchinsert;
 
 import io.ebean.BaseTestCase;
+import io.ebean.DB;
 import io.ebean.Ebean;
 import io.ebean.Transaction;
 import io.ebean.annotation.IgnorePlatform;
@@ -208,4 +209,21 @@ public class TestBatchInsertSimple extends BaseTestCase {
     return detail;
   }
 
+  @Test(expected = Test.None.class)// no exception expected
+  public void npe_addBatch_withoutAnyBindParams() {
+    try (Transaction txn = DB.beginTransaction()) {
+      // don't write code like this please ...
+      DB.sqlUpdate("update ut_master set name='DoNotDoThisPlease' where id=999999999").addBatch();
+      txn.commit();
+    }
+
+    // don't write code like the above but use bind values like:
+    try (Transaction txn = DB.beginTransaction()) {
+      DB.sqlUpdate("update ut_master set name=? where id=?")
+        .setParams("DoNotDoThisPlease", 999999999)
+        .addBatch();
+
+      txn.commit();
+    }
+  }
 }