Fixes a few sonarqube violations.

org.sat4j.core/src/main/java/org/sat4j/minisat/constraints/cnf/BinaryClause.java

@@ -49,8 +49,8 @@ import org.sat4j.specs.VarMapper;
  * @author leberre
  * @since 2.1
  */
-public abstract class BinaryClause implements Propagatable, Constr,
-        Serializable {
+public abstract class BinaryClause
+        implements Propagatable, Constr, Serializable {
 
     private static final long serialVersionUID = 1L;
 
@@ -108,7 +108,8 @@ public abstract class BinaryClause implements Propagatable, Constr,
      * @see Constr#simplify(Solver)
      */
     public boolean simplify() {
-        if (this.voc.isSatisfied(this.head) || this.voc.isSatisfied(this.tail)) {
+        if (this.voc.isSatisfied(this.head)
+                || this.voc.isSatisfied(this.tail)) {
             return true;
         }
         return false;
@@ -220,6 +221,9 @@ public abstract class BinaryClause implements Propagatable, Constr,
         if (obj == null) {
             return false;
         }
+        if (this.getClass() != obj.getClass()) {
+            return false;
+        }
         try {
             BinaryClause wcl = (BinaryClause) obj;
             if (wcl.head != this.head || wcl.tail != this.tail) {
@@ -233,7 +237,7 @@ public abstract class BinaryClause implements Propagatable, Constr,
 
     @Override
     public int hashCode() {
-        long sum = this.head + this.tail;
+        long sum = (long) this.head + this.tail;
         return (int) sum / 2;
     }
 

org.sat4j.core/src/main/java/org/sat4j/minisat/constraints/cnf/HTClause.java

@@ -128,7 +128,8 @@ public abstract class HTClause implements Propagatable, Constr, Serializable {
      * @see Constr#simplify(Solver)
      */
     public boolean simplify() {
-        if (this.voc.isSatisfied(this.head) || this.voc.isSatisfied(this.tail)) {
+        if (this.voc.isSatisfied(this.head)
+                || this.voc.isSatisfied(this.tail)) {
             return true;
         }
         for (int middleLit : this.middleLits) {
@@ -273,6 +274,8 @@ public abstract class HTClause implements Propagatable, Constr, Serializable {
         if (obj == null) {
             return false;
         }
+        if (this.getClass() != obj.getClass())
+            return false;
         try {
             HTClause wcl = (HTClause) obj;
             if (wcl.head != this.head || wcl.tail != this.tail) {
@@ -302,7 +305,7 @@ public abstract class HTClause implements Propagatable, Constr, Serializable {
 
     @Override
     public int hashCode() {
-        long sum = this.head + this.tail;
+        long sum = (long) this.head + this.tail;
         for (int p : this.middleLits) {
             sum += p;
         }

org.sat4j.core/src/main/java/org/sat4j/minisat/constraints/cnf/WLClause.java

@@ -245,6 +245,9 @@ public abstract class WLClause implements Propagatable, Constr, Serializable {
         if (obj == null) {
             return false;
         }
+        if (this.getClass() != obj.getClass()) {
+            return false;
+        }
         try {
             WLClause wcl = (WLClause) obj;
             if (this.lits.length != wcl.lits.length) {

org.sat4j.core/src/main/java/org/sat4j/minisat/core/SizeComparator.java

@@ -51,10 +51,10 @@ public class SizeComparator implements Comparator<Constr>, Serializable {
      * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
      */
     public int compare(Constr c1, Constr c2) {
-        long delta = c1.size() - c2.size();
+        int delta = c1.size() - c2.size();
         if (delta == 0) {
             return (int) Math.round(c2.getActivity() - c1.getActivity());
         }
-        return (int) delta;
+        return delta;
     }
 }
\ No newline at end of file