BAEL-5908: Single.just vs fromCallable

rxjava-modules/rxjava-core-2/src/main/java/com/baeldung/rxjava/justvscallable/EmployeeRepository.java

@@ -0,0 +1,5 @@
+package com.baeldung.rxjava.justvscallable;
+
+public interface EmployeeRepository {
+    String findById(Long id);
+}

rxjava-modules/rxjava-core-2/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>