JAVA-1470 Move 10 articles to libraries-4 module

libraries-4/src/main/java/com/baeldung/pairs/CustomPair.java

@@ -0,0 +1,33 @@
+package com.baeldung.pairs;
+
+public class CustomPair {
+
+    private String key;
+    private String value;
+    
+    public CustomPair(String key, String value) {
+        super();
+        this.key = key;
+        this.value = value;
+    }
+
+    public String getKey() {
+        return key;
+    }
+
+    public void setKey(String key) {
+        this.key = key;
+    }
+
+    public String getValue() {
+        return value;
+    }
+
+    public void setValue(String value) {
+        this.value = value;
+    }
+    
+    public Object[] getPair() {
+        return new Object[] { this.key, this.value};
+    }
+}