fixed typo

Author: Arshia Malkani

src/main/java/net/sf/jsqlparser/expression/AllComparisonExpression.java

@@ -65,7 +65,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/AnalyticExpression.java

@@ -200,7 +200,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/AnyComparisonExpression.java

@@ -76,7 +76,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/BinaryExpression.java

@@ -89,7 +89,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/CaseExpression.java

@@ -136,7 +136,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/CastExpression.java

@@ -91,7 +91,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/DateTimeLiteralExpression.java

@@ -98,9 +98,8 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 
-
 }

src/main/java/net/sf/jsqlparser/expression/DateValue.java

@@ -72,7 +72,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/DoubleValue.java

@@ -76,7 +76,7 @@ public void setLogicalType(Object inputLogicalType) {
     }
 
     @Override
-    public String getLogicalType() {
+    public Object getLogicalType() {
         return expressionType;
     }
 

src/main/java/net/sf/jsqlparser/expression/Expression.java

@@ -21,11 +21,14 @@
  */
 package net.sf.jsqlparser.expression;
 
+import java.util.*;
+
 public interface Expression {
 
     void setExpressionType(String expression);
     String getExpressionType();
 
+
     void setLogicalType(Object expression);
     Object getLogicalType();