spring-android-showcase client mvn package failed

[maoshiyi]

failure information:
[ERROR] Failed to execute goal com.jayway.maven.plugins.android.generation2:andr
oid-maven-plugin:3.9.0-rc.1:apk (default-apk) on project spring-android-showcase
-client: Error while processing transient dependencies: Failed to collect depend
encies at org.springframework.android:spring-android-rest-template:jar:2.0.0.M1
-> com.google.code.android-rome-feed-reader:android-rome-feed-reader:jar:1.0.0-r
2: Failed to read artifact descriptor for com.google.code.android-rome-feed-read
er:android-rome-feed-reader:jar:1.0.0-r2: Could not transfer artifact com.google
.code.android-rome-feed-reader:android-rome-feed-reader:pom:1.0.0-r2 from/to cen
tral (https://repo.maven.apache.org/maven2): sun.security.validator.ValidatorExc
eption: PKIX path building failed: sun.security.provider.certpath.SunCertPathBui
lderException: unable to find valid certification path to requested target -> [H
elp 1]

my maven environment:
Apache Maven 3.2.3 (33f8c3e1027c3ddde99d3cdebad2656a31e8fdf4; 2014-08-12T04:58:1
0+08:00)
Maven home: C:\tools\apache-maven-3.2.3\bin..
Java version: 1.7.0_21, vendor: Oracle Corporation
Java home: D:\Program Files\Java\jdk1.7.0_21\jre
Default locale: zh_CN, platform encoding: GBK
OS name: "windows 7", version: "6.1", arch: "x86", family: "windows"