diff --git a/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/basic/GroovySimpleTests.java b/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/basic/GroovySimpleTests.java
index fd6b3c6c6d..b9369a164a 100644
--- a/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/basic/GroovySimpleTests.java
+++ b/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/basic/GroovySimpleTests.java
@@ -1069,6 +1069,23 @@ public void testStaticProperty14() {
             "----------\n");
     }
 
+    @Test // GROOVY-10159
+    public void testStaticProperty15() {
+        //@formatter:off
+        String[] sources = {
+            "Main.groovy",
+            "public class Main {\n" +
+            "  static final String foo = 1 + 1\n" +
+            "  static main(args) {\n" +
+            "    print(foo);\n" +
+            "  }\n" +
+            "}\n",
+        };
+        //@formatter:on
+
+        runConformTest(sources, "2");
+    }
+
     @Test
     public void testClash_GRE1076() {
         //@formatter:off
diff --git a/base/org.codehaus.groovy25/src/org/apache/groovy/ast/tools/ExpressionUtils.java b/base/org.codehaus.groovy25/src/org/apache/groovy/ast/tools/ExpressionUtils.java
index 6c5492116c..08d4dd539e 100644
--- a/base/org.codehaus.groovy25/src/org/apache/groovy/ast/tools/ExpressionUtils.java
+++ b/base/org.codehaus.groovy25/src/org/apache/groovy/ast/tools/ExpressionUtils.java
@@ -82,6 +82,9 @@ public static ConstantExpression transformBinaryConstantExpression(BinaryExpress
                 Expression left = transformInlineConstants(be.getLeftExpression(), targetType);
                 Expression right = transformInlineConstants(be.getRightExpression(), targetType);
                 if (left instanceof ConstantExpression && right instanceof ConstantExpression) {
+                    // GRECLIPSE add -- GROOVY-10159
+                    if (((ConstantExpression) left).getValue() instanceof String)
+                    // GRECLIPSE end
                     return configure(be, new ConstantExpression((String) ((ConstantExpression) left).getValue() +
                             ((ConstantExpression) right).getValue()));
                 }
diff --git a/base/org.codehaus.groovy30/src/org/apache/groovy/ast/tools/ExpressionUtils.java b/base/org.codehaus.groovy30/src/org/apache/groovy/ast/tools/ExpressionUtils.java
index 6b1612c4af..1cd166c5db 100644
--- a/base/org.codehaus.groovy30/src/org/apache/groovy/ast/tools/ExpressionUtils.java
+++ b/base/org.codehaus.groovy30/src/org/apache/groovy/ast/tools/ExpressionUtils.java
@@ -77,6 +77,9 @@ public static ConstantExpression transformBinaryConstantExpression(final BinaryE
                 Expression left = transformInlineConstants(be.getLeftExpression(), targetType);
                 Expression right = transformInlineConstants(be.getRightExpression(), targetType);
                 if (left instanceof ConstantExpression && right instanceof ConstantExpression) {
+                    // GRECLIPSE add -- GROOVY-10159
+                    if (((ConstantExpression) left).getValue() instanceof String)
+                    // GRECLIPSE end
                     return configure(be, new ConstantExpression((String) ((ConstantExpression) left).getValue() + ((ConstantExpression) right).getValue()));
                 }
             }
diff --git a/base/org.codehaus.groovy40/src/org/apache/groovy/ast/tools/ExpressionUtils.java b/base/org.codehaus.groovy40/src/org/apache/groovy/ast/tools/ExpressionUtils.java
index 75e4d4f037..064bbaf8d3 100644
--- a/base/org.codehaus.groovy40/src/org/apache/groovy/ast/tools/ExpressionUtils.java
+++ b/base/org.codehaus.groovy40/src/org/apache/groovy/ast/tools/ExpressionUtils.java
@@ -76,6 +76,9 @@ public static ConstantExpression transformBinaryConstantExpression(final BinaryE
                 Expression left = transformInlineConstants(be.getLeftExpression(), targetType);
                 Expression right = transformInlineConstants(be.getRightExpression(), targetType);
                 if (left instanceof ConstantExpression && right instanceof ConstantExpression) {
+                    // GRECLIPSE add -- GROOVY-10159
+                    if (((ConstantExpression) left).getValue() instanceof String)
+                    // GRECLIPSE end
                     return configure(be, new ConstantExpression((String) ((ConstantExpression) left).getValue() + ((ConstantExpression) right).getValue()));
                 }
             }