diff --git a/user/super/com/google/gwt/emul/java/math/BigDecimal.java b/user/super/com/google/gwt/emul/java/math/BigDecimal.java
index 0cd351f..3c29c85 100644
--- a/user/super/com/google/gwt/emul/java/math/BigDecimal.java
+++ b/user/super/com/google/gwt/emul/java/math/BigDecimal.java
@@ -2608,6 +2608,12 @@
     if ((offset < last) && (val.charAt(offset) == '+')) {
       offset++;
       begin++;
+
+      // Fail if the next character is another sign.
+      if ((offset < last)
+          && (val.charAt(offset) == '+' || val.charAt(offset) == '-')) {
+        throw new NumberFormatException("For input string: \"" + val + "\"");
+      }
     }
     int counter = 0;
     boolean wasNonZero = false;
diff --git a/user/test/com/google/gwt/emultest/java/math/BigDecimalConstructorsTest.java b/user/test/com/google/gwt/emultest/java/math/BigDecimalConstructorsTest.java
index 88e0caa..aa5765c 100644
--- a/user/test/com/google/gwt/emultest/java/math/BigDecimalConstructorsTest.java
+++ b/user/test/com/google/gwt/emultest/java/math/BigDecimalConstructorsTest.java
@@ -514,6 +514,30 @@
   }
 
   /**
+   * new BigDecimal(String value) when value has multiple signs.
+   */
+  public void testConstrStringMultipleSignsStartWithPlus() {
+    String a = "+-3";
+    try {
+      new BigDecimal(a);
+      fail("NumberFormatException expected");
+    } catch (NumberFormatException expected) {
+    }
+  }
+
+  /**
+   * new BigDecimal(String value) when value has multiple signs.
+   */
+  public void testConstrStringMultipleSignsStartWithMinus() {
+    String a = "-+3";
+    try {
+      new BigDecimal(a);
+      fail("NumberFormatException expected");
+    } catch (NumberFormatException expected) {
+    }
+  }
+
+  /**
    * new BigDecimal(String value, MathContext).
    */
   public void testConstrStringMathContext() {