Minor changes in #equals for PDF primitive objects.

DEVSIX-851

Author: pavel-alay

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfBoolean.java

@@ -156,7 +156,7 @@ protected void copyContent(PdfObject from, PdfDocument document) {
     @Override
     public boolean equals(Object obj) {
         return this == obj ||
-                !(obj == null || getClass() != obj.getClass()) && value == ((PdfBoolean) obj).value;
+                obj != null && getClass() == obj.getClass() && value == ((PdfBoolean) obj).value;
     }
 
     @Override

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfLiteral.java

@@ -105,7 +105,7 @@ protected void generateContent() {
     @Override
     public boolean equals(Object o) {
         return this == o ||
-                !(o == null || getClass() != o.getClass()) && Arrays.equals(content, ((PdfLiteral) o).content);
+                o != null && getClass() == o.getClass() && Arrays.equals(content, ((PdfLiteral) o).content);
     }
 
     @Override

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfNull.java

@@ -147,7 +147,7 @@ protected void copyContent(PdfObject from, PdfDocument document) {
 
     @Override
     public boolean equals(Object obj) {
-        return this == obj || !(obj == null || getClass() != obj.getClass());
+        return this == obj || obj != null && getClass() == obj.getClass();
     }
 
     @Override

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfNumber.java

@@ -191,7 +191,7 @@ public String toString() {
     @Override
     public boolean equals(Object o) {
         return this == o ||
-                !(o == null || getClass() != o.getClass()) && Double.compare(((PdfNumber) o).value, value) == 0;
+                o != null && getClass() == o.getClass() && Double.compare(((PdfNumber) o).value, value) == 0;
     }
 
     @Override