DOC-4560 pipe/transaction examples for docs (#4038)

* DOC-4560 pipe/transaction examples for docs

* Update src/test/java/io/redis/examples/PipeTransExample.java

Co-authored-by: M Sazzadul Hoque <7600764+sazzad16@users.noreply.github.com>

---------

Co-authored-by: M Sazzadul Hoque <7600764+sazzad16@users.noreply.github.com>

src/test/java/io/redis/examples/PipeTransExample.java

@@ -0,0 +1,118 @@
+// EXAMPLE: pipe_trans_tutorial
+// REMOVE_START
+package io.redis.examples;
+
+import org.junit.Assert;
+import org.junit.Test;
+// REMOVE_END
+import java.util.List;
+
+import redis.clients.jedis.UnifiedJedis;
+import redis.clients.jedis.AbstractPipeline;
+import redis.clients.jedis.AbstractTransaction;
+import redis.clients.jedis.Response;
+
+public class PipeTransExample {
+    @Test
+    public void run() {
+        UnifiedJedis jedis = new UnifiedJedis("redis://localhost:6379");
+        // REMOVE_START
+        for (int i = 0; i < 5; i++) {
+            jedis.del(String.format("seat:%d", i));
+        }
+
+        jedis.del("counter:1", "counter:2", "counter:3", "shellpath");
+        // REMOVE_END
+
+        // STEP_START basic_pipe
+        AbstractPipeline pipe = jedis.pipelined();
+
+        for (int i = 0; i < 5; i++) {
+            pipe.set(String.format("seat:%d", i), String.format("#%d", i));
+        }
+
+        pipe.sync();
+
+        pipe = jedis.pipelined();
+
+        Response<String> resp0 = pipe.get("seat:0");
+        Response<String> resp3 = pipe.get("seat:3");
+        Response<String> resp4 = pipe.get("seat:4");
+
+        pipe.sync();
+
+        // Responses are available after the pipeline has executed.
+        System.out.println(resp0.get()); // >>> #0
+        System.out.println(resp3.get()); // >>> #3
+        System.out.println(resp4.get()); // >>> #4
+        // STEP_END
+        // REMOVE_START
+        Assert.assertEquals("#0", resp0.get());
+        Assert.assertEquals("#3", resp3.get());
+        Assert.assertEquals("#4", resp4.get());
+        // REMOVE_END
+
+        // STEP_START basic_trans
+        AbstractTransaction trans = jedis.multi();
+
+        trans.incrBy("counter:1", 1);
+        trans.incrBy("counter:2", 2);
+        trans.incrBy("counter:3", 3);
+
+        trans.exec();
+
+        System.out.println(jedis.get("counter:1")); // >>> 1
+        System.out.println(jedis.get("counter:2")); // >>> 2
+        System.out.println(jedis.get("counter:3")); // >>> 3
+        // STEP_END
+        // REMOVE_START
+        Assert.assertEquals("1", jedis.get("counter:1"));
+        Assert.assertEquals("2", jedis.get("counter:2"));
+        Assert.assertEquals("3", jedis.get("counter:3"));
+        // REMOVE_END
+
+        // STEP_START trans_watch
+        // Set initial value of `shellpath`.
+        jedis.set("shellpath", "/usr/syscmds/");
+
+        // Start the transaction and watch the key we are about to update.
+        trans = jedis.transaction(false); // create a Transaction object without sending MULTI command
+        trans.watch("shellpath"); // send WATCH command(s)
+        trans.multi(); // send MULTI command
+
+        String currentPath = jedis.get("shellpath");
+        String newPath = currentPath + ":/usr/mycmds/";
+
+        // Commands added to the `trans` object
+        // will be buffered until `trans.exec()` is called.
+        Response<String> setResult = trans.set("shellpath", newPath);
+        List<Object> transResults = trans.exec();
+
+        // The `exec()` call returns null if the transaction failed.
+        if (transResults != null) {
+            // Responses are available if the transaction succeeded.
+            System.out.println(setResult.get()); // >>> OK
+
+            // You can also get the results from the list returned by
+            // `trans.exec()`.
+            for (Object item: transResults) {
+                System.out.println(item);
+            }
+            // >>> OK
+
+            System.out.println(jedis.get("shellpath"));
+            // >>> /usr/syscmds/:/usr/mycmds/
+        }
+        // STEP_END
+        // REMOVE_START
+        Assert.assertEquals("/usr/syscmds/:/usr/mycmds/", jedis.get("shellpath"));
+        Assert.assertEquals("OK", setResult.get());
+        Assert.assertEquals(1, transResults.size());
+        Assert.assertEquals("OK", transResults.get(0).toString());
+        // REMOVE_END
+
+        // HIDE_START
+        jedis.close();
+    }   
+}
+// HIDE_END