The Value of 0xFF Number and Its Uses With & Operation in Java Article by Abdallah Sawan

java-numbers-4/src/main/java/com/baeldung/number_0xff/Number0xff.java

@@ -0,0 +1,20 @@
+package com.baeldung.number_0xff;
+
+public class Number0xff {
+
+    public static int getRedColor(int rgba) {
+        return rgba >> 24 & 0xff;
+    }
+
+    public static int getGreenColor(int rgba) {
+        return rgba >> 16 & 0xff;
+    }
+
+    public static int getBlueColor(int rgba) {
+        return rgba >> 8 & 0xff;
+    }
+
+    public static int getAlfa(int rgba) {
+        return rgba >> rgba & 0xff;
+    }
+}

java-numbers-4/src/test/java/com/baeldung/number_0xff/Number0xffUnitTest.java

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+package com.baeldung.number_0xff;
+
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+public class Number0xffUtitTest {
+
+    @Test
+    public void test0xFFAssignedToInteger() {
+        int x = 0xff;
+        int expectedValue = 255;
+        assertEquals(x, expectedValue);
+    }
+
+    @Test
+    public void test0xFFAssignedToByte() {
+        byte y = (byte) 0xff;
+        int expectedValue = -1;
+        assertEquals(x, expectedValue);
+    }
+
+    @Test
+    public void givenColor_thenExtractRedColor() {
+        int rgba = 272214023;
+        int expectedValue = 64;
+        assertEquals(Number0xff.getRedColor(rgba), expectedValue);
+    }
+
+    @Test
+    public void givenColor_thenExtractGreenColor() {
+        int rgba = 272214023;
+        int expectedValue = 57;
+        assertEquals(Number0xff.getGreenColor(rgba), expectedValue);
+    }
+
+    @Test
+    public void givenColor_thenExtractBlueColor() {
+        int rgba = 272214023;
+        int expectedValue = 168;
+        assertEquals(Number0xff.getBlueColor(rgba), expectedValue);
+    }
+
+    @Test
+    public void givenColor_thenExtractAlfa() {
+        int rgba = 272214023;
+        int expectedValue = 7;
+        assertEquals(Number0xff.getAlfa(rgba), expectedValue);
+    }
+}