<#assign t = JspTaglibs["http://freemarker.org/test/taglibs/test"]>

a1: ${a1!'-'}
<@t.getAndSet name="a1" value=0 />
a1: ${a1}
<@t.getAndSet name="a1" value=1 scope="page" />
a1: ${a1}
<@t.getAndSet name="a1" value=2 scope="request" />
<@t.getAndSet name="a1" value=3 scope="session" />
<@t.getAndSet name="a1" value=4 scope="application" />
Request.a1: ${Request.a1}
Session.a1: ${Session.a1}
Application.a1: ${Application.a1}
a1: ${a1}
<@t.getAndSet name="a1" value=null scope="page" />
a1: ${a1}
<@t.getAndSet name="a1" value=null scope="request" />
a1: ${a1}
<@t.getAndSet name="a1" value=null scope="session" />
a1: ${a1}
<@t.getAndSet name="a1" value=null scope="application" />
a1: ${a1!'-'}

a2: ${a2!'-'}
<@t.getAndSet name="a2" value=4 scope="application" />
a2: ${a2}
<@t.getAndSet name="a2" value=3 scope="session" />
a2: ${a2}
<@t.getAndSet name="a2" value=2 scope="request" />
a2: ${a2}
<@t.getAndSet name="a2" value=1 scope="page" />
a2: ${a2}

<#global a1 = 'G1'>
${a1}
<@t.getAndSet name="a1" value='P1' scope="page" />
${a1}

<#global a2 = 'G2'>
${a2}
<@t.getAndSet name="a2" value='P2' scope="page" />
${a2}

Values created in the template:
<#global a = 's'>
String: <@t.attributeInfo name='a' />
<#global a = 1>
Number: <@t.attributeInfo name='a' />
<#global a = true>
Boolean: <@t.attributeInfo name='a' />
<#global a = '2014-12-20T18:19+02:00'?datetime.iso>
Date-time: <@t.attributeInfo name='a' />
<#global a = [1, 2, 3]>
Sequence: <@t.attributeInfo name='a' />
<#global a = {'a': 1, 'b': 2, 'c': 3}>
Hash: <@t.attributeInfo name='a' />

Values created in Java:
<#global a = linkedList>
LinkedList: <@t.attributeInfo name='a' />
<#global a = arrayList>
ArrayList: <@t.attributeInfo name='a' />
<#global a = myList>
MyList: <@t.attributeInfo name='a' />
<#global a = linkedHashMap>
LinkedHashMap: <@t.attributeInfo name='a' />
<#global a = treeMap>
TreeMap: <@t.attributeInfo name='a' />
<#global a = myMap>
MyMap: <@t.attributeInfo name='a' />
<#global a = treeSet>
TreeSet: <@t.attributeInfo name='a' />