Frequency of each character from a word in java

class freqch
{
public void strn(String st)
{
int i,j,c;
char ch;
for(i=65;i<=90;i++)
{
c=0;
for(j=0;j<st.length();j++)
{
ch=st.charAt(j);
if(ch == (char)i || ch == (char)(i+32))
c++;
}
if(c != 0)
System.out.println((char)i+"\t"+c);
}
}
}