Add java and jvm section

src/SUMMARY.md

@@ -26,6 +26,8 @@
   - [Web](./dev/web/main.md)
     - [front](./dev/web/front/main.md)
       - [babel and babel-preset-stage-2](./dev/web/front/babel-preset-stage-2.md)
+  - [JVM](./dev/jvm/main.md)
+    - [Java](./dev/jvm/java/main.md)
   - [Regex](./dev/regex/main.md)
   - [Tools](./dev/tools/main.md)
     - [Git](./dev/tools/git.md)

src/dev/jvm/java/main.md

@@ -0,0 +1,7 @@
+# Java
+
+## Defaults
+
+Java uses `int` (64 bits) as default type for integer numbers
+
+Java uses `double` as default type for floating point number (`double` precision `float` precision)

src/dev/jvm/main.md

@@ -0,0 +1 @@
+# JVM