code related to concatenate strings in Groovy (#6277)

core-groovy/src/main/groovy/com/baeldung/strings/Concatenate.groovy

@@ -0,0 +1,43 @@
+package com.baeldung.strings;
+
+class Concatenate {
+    String first = 'Hello'
+    String last = 'Groovy'
+  
+    String doSimpleConcat() {
+        return 'My name is ' + first + ' ' + last
+    }
+
+    String doConcatUsingGString() {
+        return "My name is $first $last"
+    }
+
+    String doConcatUsingGStringClosures() {
+        return "My name is ${-> first} ${-> last}"
+    }
+
+    String doConcatUsingStringConcatMethod() {
+        return 'My name is '.concat(first).concat(' ').concat(last)
+    }
+
+    String doConcatUsingLeftShiftOperator() {
+        return 'My name is ' << first << ' ' << last
+    }
+    
+    String doConcatUsingArrayJoinMethod() {
+        return ['My name is', first, last].join(' ')
+    }
+
+    String doConcatUsingArrayInjectMethod() {
+        return  [first,' ', last]
+          .inject(new StringBuffer('My name is '), { initial, name -> initial.append(name); return initial }).toString()
+    }
+ 
+    String doConcatUsingStringBuilder() {
+        return new StringBuilder().append('My name is ').append(first).append(' ').append(last)
+    }
+
+    String doConcatUsingStringBuffer() {
+        return new StringBuffer().append('My name is ').append(first).append(' ').append(last)
+    }
+}