The document discusses the capabilities and implementations of functional-reactive programming in Java 8 and 9, focusing on the use of functional interfaces and patterns like virtual proxies. It highlights the improvements in design and code structuring brought about by these enhancements, alongside examples of implementations in various industries such as finance and government. Additionally, it covers memoization techniques and provides source code references for practical application.

1. prepare for…
Functional-Reactive
…with Core Java 8/9

2. @SvenRuppert
has been coding java since 1996
2

3. @SvenRuppert
has been coding java since 1996
Projects in the field of:
•Automobile-industry
•Energy
•Finance / Leasing
•Space- Satellit-
•Government / UN / World-bank
Where?
•Europe
•Asia - from India up to Malaysia
2

4. Small AddOns
based on Java8
@SvenRuppert

5. 4
@SvenRuppertJava8 - Optional<T>

6. 4
@SvenRuppertJava8 - Optional<T>

7. 4
@SvenRuppertJava8 - Optional<T>

8. 4
@SvenRuppertJava8 - Optional<T>

9. 4
@SvenRuppertJava8 - Optional<T>

10. 4
@SvenRuppertJava8 - Optional<T>
Optional - [ Int, Double, Long ]

11. 5
@SvenRuppertJava8 - Functional Interfaces

12. 5
@SvenRuppertJava8 - Functional Interfaces

13. 5
@SvenRuppertJava8 - Functional Interfaces

14. 6
@SvenRuppertJava8 - Functional Interfaces

15. 7
@SvenRuppertJava8 - Functional Interfaces

16. 7
@SvenRuppertJava8 - Functional Interfaces

17. 7
@SvenRuppertJava8 - Functional Interfaces

18. 7
@SvenRuppertJava8 - Functional Interfaces

19. 7
@SvenRuppertJava8 - Functional Interfaces

20. 7
@SvenRuppertJava8 - Functional Interfaces

21. 7
@SvenRuppertJava8 - Functional Interfaces

22. 8
@SvenRuppertJava8 - Functional Interfaces

23. 8
@SvenRuppertJava8 - Functional Interfaces

24. 8
@SvenRuppertJava8 - Functional Interfaces

25. 9
@SvenRuppertJava9 - Functional Interfaces
Java9 - JEP213

26. Functions
how use Functions…
@SvenRuppert

27. Functions - Java8
11
@SvenRuppert

28. Functions - Java8
11
@SvenRuppert

29. Functions - Java8
11
@SvenRuppert

30. Functions - Java8
11
@SvenRuppert

31. Functions - Java8
11
@SvenRuppert

32. Functions - Java8
11
@SvenRuppert

33. Functions - Java8
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@SvenRuppert

34. Functions - Java8
12
@SvenRuppert

35. Functions - Java8
12
@SvenRuppert

36. Functions - Java8
12
@SvenRuppert

37. Functions - Java8
12
@SvenRuppert

38. Functions - Java8
12
@SvenRuppert

39. Functions - Java8
12
@SvenRuppert

40. Functions - Java8
12
@SvenRuppert

41. Functions - Java8
12
@SvenRuppert

42. Functions - Java8
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@SvenRuppert

43. Functions - Java8
13
@SvenRuppert

44. Functions - Java8
13
@SvenRuppert

45. Functions - Java8
13
@SvenRuppert

46. Functions - Java8
13
@SvenRuppert

47. Functions - Java8
13
@SvenRuppert

48. Functions - Java8
14
@SvenRuppert

49. Functions - Java8
14
@SvenRuppert

50. Functions - Java8
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@SvenRuppert

51. Functions - Java8
15
@SvenRuppert

52. Functions - Java8
15
@SvenRuppert

53. Functions - Java8
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@SvenRuppert

54. Functions - Java8
16
@SvenRuppert

55. Functions - Java8
17
@SvenRuppert

56. Refactoring example
based on Java8
@SvenRuppert

57. 19
@SvenRuppertJava8 - Functional Interfaces - Example
typical legacy implementation

58. 20
@SvenRuppertJava8 - Functional Interfaces - Example
typical legacy implementation

59. 21
@SvenRuppertJava8 - Functional Interfaces - Example

60. 21
@SvenRuppertJava8 - Functional Interfaces - Example

61. 21
@SvenRuppertJava8 - Functional Interfaces - Example

62. 21
@SvenRuppertJava8 - Functional Interfaces - Example

63. 21
@SvenRuppertJava8 - Functional Interfaces - Example

64. 21
@SvenRuppertJava8 - Functional Interfaces - Example

65. 22
@SvenRuppertJava8 - Functional Interfaces - Example

66. 22
@SvenRuppertJava8 - Functional Interfaces - Example

67. 22
@SvenRuppertJava8 - Functional Interfaces - Example

68. 22
@SvenRuppertJava8 - Functional Interfaces - Example

69. 22
@SvenRuppertJava8 - Functional Interfaces - Example

70. 23
@SvenRuppertJava8 - Functional Interfaces - Example

71. 23
@SvenRuppertJava8 - Functional Interfaces - Example

72. 23
@SvenRuppertJava8 - Functional Interfaces - Example

73. 24
@SvenRuppertJava8 - Functional Interfaces - Example

74. 24
@SvenRuppertJava8 - Functional Interfaces - Example

75. 24
@SvenRuppertJava8 - Functional Interfaces - Example

76. 24
@SvenRuppertJava8 - Functional Interfaces - Example

77. 25
@SvenRuppertJava8 - Functional Interfaces - Example

78. 25
@SvenRuppertJava8 - Functional Interfaces - Example

79. 26
@SvenRuppertJava8 - Functional Interfaces - Example
Sourcecode is on github

80. 26
@SvenRuppertJava8 - Functional Interfaces - Example
Sourcecode is on github

81. Pattern in Java 8/9
how pattern will change…
@SvenRuppert

82. Virtual Proxy
28
@SvenRuppert

83. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}

84. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}
What could we
change now ?

85. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}
What could we
change now ? Virtual Proxy:
create the Delegator later

86. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}
What could we
change now ? Virtual Proxy:
create the Delegator later
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}

87. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}
What could we
change now ? Virtual Proxy:
create the Delegator later
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}

88. Virtual Proxy
28
@SvenRuppert
public class ServiceProxy implements Service {
private Service service = new ServiceImpl();
public String work(String txt) { return service.work(txt); }
}
What could we
change now ? Virtual Proxy:
create the Delegator later
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}

89. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}

90. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}

91. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}
This is NOT ThreadSafe

92. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}
This is NOT ThreadSafe

93. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}
This is NOT ThreadSafe
fixed decision for
an implementation

94. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}
This is NOT ThreadSafe
fixed decision for
an implementation

95. Virtual Proxy
29
@SvenRuppert
public class VirtualService implements Service {
private Service service = null;
public String work(String txt) {
if(service == null) { service = new ServiceImpl(); }
return service.work(txt);
}
}
This is NOT ThreadSafe
fixed decision for
an implementation
how to combine it with
a FactoryPattern ?

96. Virtual Proxy
30
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }

97. Virtual Proxy
30
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }

98. Virtual Proxy
30
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public interface ServiceFactory {
Service createInstance();
}

99. Virtual Proxy
30
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public interface ServiceFactory {
Service createInstance();
}

100. Virtual Proxy
30
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public interface ServiceFactory {
Service createInstance();
}
public interface ServiceStrategyFactory {
Service realSubject(ServiceFactory factory);
}

101. Virtual Proxy - Not - ThreadSafe
31
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }

102. Virtual Proxy - Not - ThreadSafe
31
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }

103. Virtual Proxy - Not - ThreadSafe
31
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
private ServiceFactory serviceFactory = ServiceImpl::new;

104. Virtual Proxy - Not - ThreadSafe
31
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
private ServiceFactory serviceFactory = ServiceImpl::new;

105. Virtual Proxy - Not - ThreadSafe
31
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceStrategyFactoryImpl implements ServiceStrategyFactory {
Service realSubject;
public Service realSubject(final ServiceFactory factory) {
if (realSubject == null) {
realSubject = factory.createInstance();
}
return realSubject;
}
}
private ServiceFactory serviceFactory = ServiceImpl::new;

106. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }

107. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {

108. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;

109. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();

110. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {

111. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
}
}

112. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
return
}
}

113. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
return strategyFactory
}
}

114. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
return strategyFactory .realSubject(
}
}

115. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
return strategyFactory .realSubject(serviceFactory
}
}

116. Virtual Proxy - Not - ThreadSafe
32
@SvenRuppert
if(service == null) { service = new ServiceImpl(); }
public class ServiceProxy implements Service {
private ServiceFactory serviceFactory = ServiceImpl::new;
private ServiceStrategyFactory strategyFactory = new ServiceStrategyFactoryImpl();
public String work(String txt) {
return strategyFactory .realSubject(serviceFactory).work(txt);
}
}

117. Virtual Proxy - Show some code….
33
@SvenRuppert

118. Virtual Proxy - Show some code….
33
@SvenRuppert

119. Virtual Proxy - Show some code….
33
@SvenRuppert

120. Virtual Proxy - Show some code….
33
@SvenRuppert

121. Virtual Proxy - Show some code….
34
@SvenRuppert

122. Virtual Proxy - Show some code….
34
@SvenRuppert

123. Virtual Proxy - Show some code….
34
@SvenRuppert

124. Virtual Proxy - Show some code….
34
@SvenRuppert

125. Virtual Proxy - Show some code….
35
@SvenRuppert

126. Virtual Proxy - Show some code….
35
@SvenRuppert

127. Virtual Proxy - Show some code….
35
@SvenRuppert

128. Virtual Proxy - Show some code….
35
@SvenRuppert

129. Virtual Proxy - Show some code….
36
@SvenRuppert

130. Virtual Proxy - Show some code….
36
@SvenRuppert

131. Virtual Proxy - Show some code….
37
@SvenRuppert

132. Virtual Proxy - Show some code….
37
@SvenRuppert

133. Virtual Proxy - Show some code….
37
@SvenRuppert

134. Virtual Proxy - Show some code….
37
@SvenRuppert

135. Virtual Proxy - Show some code….
37
@SvenRuppert

136. Virtual Proxy - Show some code….
38
@SvenRuppert

137. Virtual Proxy - Show some code….
38
@SvenRuppert

138. Virtual Proxy - Show some code….
39
@SvenRuppert

139. Virtual Proxy - Show some code….
39
@SvenRuppert

140. Virtual Proxy - Show some code….
40
@SvenRuppert

141. Virtual Proxy - Show some code….
40
@SvenRuppert

142. Virtual Proxy - Show some code….
41
@SvenRuppert

143. Virtual Proxy - Show some code….
41
@SvenRuppert

144. Virtual Proxy - Show some code….
42
@SvenRuppert

145. Virtual Proxy - Show some code….
42
@SvenRuppert

146. Interpreter - pre Java8
43
@SvenRuppert

147. Interpreter - pre Java8
44
@SvenRuppert

148. Interpreter - pre Java8
44
@SvenRuppert

149. Interpreter - pre Java8
44
@SvenRuppert

150. Interpreter - pre Java8
45
@SvenRuppert

151. Interpreter - pre Java8
45
@SvenRuppert

152. Interpreter - pre Java8
45
@SvenRuppert

153. Interpreter - pre Java8
46
@SvenRuppert

154. Interpreter - pre Java8
46
@SvenRuppert

155. Interpreter - pre Java8
46
@SvenRuppert

156. Interpreter - pre Java8
46
@SvenRuppert

157. Interpreter - Java8 - Java9
47
@SvenRuppert

158. Interpreter - Java8 - Java9
47
@SvenRuppert

159. Interpreter - Java8 - Java9
47
@SvenRuppert

160. Interpreter - Java8 - Java9
48
@SvenRuppert
Main Idea - DataStructure to Function

161. Interpreter - Java8 - Java9
48
@SvenRuppert
Main Idea - DataStructure to Function

162. Interpreter - Java8 - Java9
48
@SvenRuppert
Main Idea - DataStructure to Function

163. Interpreter - Java8 - Java9
49
@SvenRuppert

164. Interpreter - Java8 - Java9
49
@SvenRuppert

165. Memoizing
pure functional behavior - show Source code
@SvenRuppert

166. @SvenRuppert
Memoizing @SvenRuppert

167. @SvenRuppert
Memoizing @SvenRuppert

168. @SvenRuppert
Memoizing @SvenRuppert

169. @SvenRuppert
Memoizing @SvenRuppert

170. @SvenRuppert
Memoizing @SvenRuppert

171. @SvenRuppert
Memoizing @SvenRuppert

172. @SvenRuppert
Memoizing @SvenRuppert

173. @SvenRuppert
Memoizing @SvenRuppert

174. @SvenRuppert
Memoizing @SvenRuppert

175. @SvenRuppert
Memoizing @SvenRuppert

176. @SvenRuppert
Memoizing @SvenRuppert

177. Reactive stuff
how use Functions… async…
@SvenRuppert

178. Observer
63
@SvenRuppert

179. Observer
63
@SvenRuppert

180. Observer
63
@SvenRuppert

181. Observer
63
@SvenRuppert

182. Observer
63
@SvenRuppert

183. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture

184. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process

185. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread

186. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber

187. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber

188. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage

189. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage

190. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage

191. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage CompletionStage

192. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage CompletionStage

193. 64
@SvenRuppertJava8 - Concurrency - CompletableFuture
Process
Thread
Fiber
CompletionStage CompletionStage CompletionStage

194. 65
@SvenRuppertJava8 - Concurrency - CompletableFuture

195. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture

196. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Value A

197. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Value A Value B

198. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Value A Value B

199. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Value A Value B

200. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A Value B

201. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A Value B

202. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Value B

203. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Value B Value C

204. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Value B Value C

205. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Value B Value C

206. 66
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Result
Value B Value C

207. 67
@SvenRuppertJava8 - Concurrency - CompletableFuture

208. 67
@SvenRuppertJava8 - Concurrency - CompletableFuture

209. 67
@SvenRuppertJava8 - Concurrency - CompletableFuture

210. 68
@SvenRuppertJava8 - Concurrency - CompletableFuture

211. 68
@SvenRuppertJava8 - Concurrency - CompletableFuture

212. 68
@SvenRuppertJava8 - Concurrency - CompletableFuture

213. 69
@SvenRuppertJava8 - Concurrency - CompletableFuture

214. 69
@SvenRuppertJava8 - Concurrency - CompletableFuture

215. 70
@SvenRuppertJava8 - Concurrency - CompletableFuture

216. 70
@SvenRuppertJava8 - Concurrency - CompletableFuture

217. 70
@SvenRuppertJava8 - Concurrency - CompletableFuture

218. 71
@SvenRuppertJava8 - Concurrency - CompletableFuture

219. 71
@SvenRuppertJava8 - Concurrency - CompletableFuture

220. 71
@SvenRuppertJava8 - Concurrency - CompletableFuture

221. 72
@SvenRuppertJava8 - Concurrency - CompletableFuture

222. 72
@SvenRuppertJava8 - Concurrency - CompletableFuture

223. 72
@SvenRuppertJava8 - Concurrency - CompletableFuture

224. 73
@SvenRuppertJava8 - Concurrency - CompletableFuture

225. 73
@SvenRuppertJava8 - Concurrency - CompletableFuture

226. 74
@SvenRuppertJava8 - Concurrency - CompletableFuture

227. 74
@SvenRuppertJava8 - Concurrency - CompletableFuture

228. 74
@SvenRuppertJava8 - Concurrency - CompletableFuture

229. 74
@SvenRuppertJava8 - Concurrency - CompletableFuture

230. 75
@SvenRuppertJava8 - Concurrency - CompletableFuture
Operator 1
Value A
Operator 2a
Result
Value B Value C

231. Java 9
some nice news…
@SvenRuppert

232. Java9 - Optional
77
@SvenRuppert

233. Java9 - Optional
77
@SvenRuppert

234. Java9 - Optional
77
@SvenRuppert

235. Java9 - Optional
77
@SvenRuppert

236. Java9 - Optional
77
@SvenRuppert

237. Java9 - JEP266
78
@SvenRuppert

238. Java9 - JEP266
78
@SvenRuppert
we got Publisher / Subscriber

239. Java9 - JEP266
78
@SvenRuppert
we got Publisher / Subscriber

240. Summary
79
@SvenRuppert
places to read more about it

241. Summary
79
@SvenRuppert
places to read more about it
www.functional-reactive.org

242. Summary
79
@SvenRuppert
places to read more about it
www.functional-reactive.org

243. Summary
79
@SvenRuppert
places to read more about it
www.functional-reactive.org
www.java-9.org

244. Summary
80
@SvenRuppert
Now it is time to relax again ;-)

245. Summary
81
@SvenRuppert
please, follow me ;-)
@SvenRuppert

246. Summary
81
@SvenRuppert
please, follow me ;-)
@SvenRuppert
Thank You !!!