diff --git a/common/src/main/java/com/highgo/cloud/util/toolkit/StringUtil.java b/common/src/main/java/com/highgo/cloud/util/toolkit/StringUtil.java
index 9398671..0bcc35d 100644
--- a/common/src/main/java/com/highgo/cloud/util/toolkit/StringUtil.java
+++ b/common/src/main/java/com/highgo/cloud/util/toolkit/StringUtil.java
@@ -834,7 +834,7 @@ public static int lastIndexOf(final CharSequence str, final CharSequence searchS
             return str.toString().lastIndexOf(searchStr.toString(), fromIndex);
         }
 
-        for (int i = fromIndex; i > 0; i--) {
+        for (int i = fromIndex; i >= 0; i--) {
             if (isSubEquals(str, i, searchStr, 0, searchStr.length(), true)) {
                 return i;
             }
@@ -969,7 +969,7 @@ public static boolean equals(CharSequence str1, CharSequence str2, boolean ignor
         if (ignoreCase) {
             return str1.toString().equalsIgnoreCase(str2.toString());
         } else {
-            return str1.equals(str2);
+            return str1.toString().equals(str2.toString());
         }
     }
 
diff --git a/tests/StringUtilCharSequenceEqualsRegression.java b/tests/StringUtilCharSequenceEqualsRegression.java
new file mode 100644
index 0000000..6f9182d
--- /dev/null
+++ b/tests/StringUtilCharSequenceEqualsRegression.java
@@ -0,0 +1,47 @@
+import com.highgo.cloud.util.toolkit.StringUtil;
+
+/** Exercises the complete production class and its real Spring superclass. */
+public final class StringUtilCharSequenceEqualsRegression {
+    private static int failures;
+
+    private static void check(String name, boolean expected, boolean actual) {
+        if (expected != actual) {
+            failures++;
+            System.err.println("FAIL " + name + ": expected " + expected + " but was " + actual);
+        } else {
+            System.out.println("PASS " + name);
+        }
+    }
+
+    public static void main(String[] args) {
+        check("distinct-builders-two-argument", true,
+                StringUtil.equals(new StringBuilder("same"), new StringBuilder("same")));
+        check("distinct-buffers-explicit-false", true,
+                StringUtil.equals(new StringBuffer("same"), new StringBuffer("same"), false));
+        check("string-to-builder", true,
+                StringUtil.equals("same", new StringBuilder("same")));
+        check("builder-to-string", true,
+                StringUtil.equals(new StringBuilder("same"), "same"));
+        check("buffer-to-builder", true,
+                StringUtil.equals(new StringBuffer("same"), new StringBuilder("same"), false));
+        check("builder-to-buffer", true,
+                StringUtil.equals(new StringBuilder("same"), new StringBuffer("same"), false));
+
+        check("string-value-control", true,
+                StringUtil.equals(new String("same"), new String("same")));
+        check("unequal-content-control", false,
+                StringUtil.equals(new StringBuilder("left"), new StringBuffer("right")));
+        check("case-sensitive-control", false,
+                StringUtil.equals(new StringBuilder("Same"), new StringBuffer("same"), false));
+        check("ignore-case-control", true,
+                StringUtil.equalsIgnoreCase(new StringBuilder("Same"), new StringBuffer("same")));
+        StringBuilder shared = new StringBuilder("same");
+        check("same-instance-control", true, StringUtil.equals(shared, shared));
+        check("both-null-control", true, StringUtil.equals(null, null));
+        check("left-null-control", false, StringUtil.equals(null, new StringBuilder("same")));
+        check("right-null-control", false, StringUtil.equals(new StringBuffer("same"), null, false));
+        if (failures != 0) {
+            throw new AssertionError(failures + " CharSequence equality cases failed");
+        }
+    }
+}
diff --git a/tests/StringUtilReverseSearchRegression.java b/tests/StringUtilReverseSearchRegression.java
new file mode 100644
index 0000000..edda37b
--- /dev/null
+++ b/tests/StringUtilReverseSearchRegression.java
@@ -0,0 +1,40 @@
+import com.highgo.cloud.util.toolkit.StringUtil;
+
+/** JDK assertion runner; the complete production class uses real Spring Core. */
+public final class StringUtilReverseSearchRegression {
+    private static int failures;
+
+    private static void check(String name, int expected, int actual) {
+        if (expected != actual) {
+            failures++;
+            System.err.println("FAIL " + name + ": expected " + expected + " but was " + actual);
+        } else {
+            System.out.println("PASS " + name);
+        }
+    }
+
+    public static void main(String[] args) {
+        check("two-argument-prefix", 0,
+                StringUtil.lastIndexOfIgnoreCase("ABCxyz", "abc"));
+        check("three-argument-zero-start", 0,
+                StringUtil.lastIndexOfIgnoreCase("abcABC", "abc", 0));
+        check("generic-identical-case-at-zero", 0,
+                StringUtil.lastIndexOf("abc", "abc", 0, true));
+        check("charsequence-prefix", 0,
+                StringUtil.lastIndexOfIgnoreCase(
+                        new StringBuilder("AbCd"), new StringBuilder("aB"), 4));
+
+        check("case-sensitive-zero-control", 0,
+                StringUtil.lastIndexOf("abc", "abc", 0, false));
+        check("later-match-control", 3,
+                StringUtil.lastIndexOfIgnoreCase("aBcAbC", "abc"));
+        check("absent-control", -1,
+                StringUtil.lastIndexOfIgnoreCase("abc", "z"));
+        check("empty-needle-control", 0,
+                StringUtil.lastIndexOfIgnoreCase("abc", "", 0));
+        if (failures != 0) {
+            throw new AssertionError(failures + " reverse-search cases failed");
+        }
+    }
+}
+